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view src/mail/ngx_mail_parse.c @ 7690:8253424d1aff

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Added size check to ngx_http_alloc_large_header_buffer(). This ensures that copying won't write more than the buffer size even if the buffer comes from hc->free and it is smaller than the large client header buffer size in the virtual host configuration. This might happen if size of large client header buffers is different in name-based virtual hosts, similarly to the problem with number of buffers fixed in 6926:e662cbf1b932.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 06 Aug 2020 05:02:22 +0300
parents bcb107bb89cd
children 6a81d96d3733
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>
#include <ngx_mail.h>
#include <ngx_mail_pop3_module.h>
#include <ngx_mail_imap_module.h>
#include <ngx_mail_smtp_module.h>


ngx_int_t
ngx_mail_pop3_parse_command(ngx_mail_session_t *s)
{
    u_char      ch, *p, *c, c0, c1, c2, c3;
    ngx_str_t  *arg;
    enum {
        sw_start = 0,
        sw_spaces_before_argument,
        sw_argument,
        sw_almost_done
    } state;

    state = s->state;

    for (p = s->buffer->pos; p < s->buffer->last; p++) {
        ch = *p;

        switch (state) {

        /* POP3 command */
        case sw_start:
            if (ch == ' ' || ch == CR || ch == LF) {
                c = s->buffer->start;

                if (p - c == 4) {

                    c0 = ngx_toupper(c[0]);
                    c1 = ngx_toupper(c[1]);
                    c2 = ngx_toupper(c[2]);
                    c3 = ngx_toupper(c[3]);

                    if (c0 == 'U' && c1 == 'S' && c2 == 'E' && c3 == 'R')
                    {
                        s->command = NGX_POP3_USER;

                    } else if (c0 == 'P' && c1 == 'A' && c2 == 'S' && c3 == 'S')
                    {
                        s->command = NGX_POP3_PASS;

                    } else if (c0 == 'A' && c1 == 'P' && c2 == 'O' && c3 == 'P')
                    {
                        s->command = NGX_POP3_APOP;

                    } else if (c0 == 'Q' && c1 == 'U' && c2 == 'I' && c3 == 'T')
                    {
                        s->command = NGX_POP3_QUIT;

                    } else if (c0 == 'C' && c1 == 'A' && c2 == 'P' && c3 == 'A')
                    {
                        s->command = NGX_POP3_CAPA;

                    } else if (c0 == 'A' && c1 == 'U' && c2 == 'T' && c3 == 'H')
                    {
                        s->command = NGX_POP3_AUTH;

                    } else if (c0 == 'N' && c1 == 'O' && c2 == 'O' && c3 == 'P')
                    {
                        s->command = NGX_POP3_NOOP;
#if (NGX_MAIL_SSL)
                    } else if (c0 == 'S' && c1 == 'T' && c2 == 'L' && c3 == 'S')
                    {
                        s->command = NGX_POP3_STLS;
#endif
                    } else {
                        goto invalid;
                    }

                } else {
                    goto invalid;
                }

                switch (ch) {
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;
            }

            if ((ch < 'A' || ch > 'Z') && (ch < 'a' || ch > 'z')) {
                goto invalid;
            }

            break;

        case sw_spaces_before_argument:
            switch (ch) {
            case ' ':
                break;
            case CR:
                state = sw_almost_done;
                s->arg_end = p;
                break;
            case LF:
                s->arg_end = p;
                goto done;
            default:
                if (s->args.nelts <= 2) {
                    state = sw_argument;
                    s->arg_start = p;
                    break;
                }
                goto invalid;
            }
            break;

        case sw_argument:
            switch (ch) {

            case ' ':

                /*
                 * the space should be considered as part of the at username
                 * or password, but not of argument in other commands
                 */

                if (s->command == NGX_POP3_USER
                    || s->command == NGX_POP3_PASS)
                {
                    break;
                }

                /* fall through */

            case CR:
            case LF:
                arg = ngx_array_push(&s->args);
                if (arg == NULL) {
                    return NGX_ERROR;
                }
                arg->len = p - s->arg_start;
                arg->data = s->arg_start;
                s->arg_start = NULL;

                switch (ch) {
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;

            default:
                break;
            }
            break;

        case sw_almost_done:
            switch (ch) {
            case LF:
                goto done;
            default:
                goto invalid;
            }
        }
    }

    s->buffer->pos = p;
    s->state = state;

    return NGX_AGAIN;

done:

    s->buffer->pos = p + 1;

    if (s->arg_start) {
        arg = ngx_array_push(&s->args);
        if (arg == NULL) {
            return NGX_ERROR;
        }
        arg->len = s->arg_end - s->arg_start;
        arg->data = s->arg_start;
        s->arg_start = NULL;
    }

    s->state = (s->command != NGX_POP3_AUTH) ? sw_start : sw_argument;

    return NGX_OK;

invalid:

    s->state = sw_start;
    s->arg_start = NULL;

    return NGX_MAIL_PARSE_INVALID_COMMAND;
}


ngx_int_t
ngx_mail_imap_parse_command(ngx_mail_session_t *s)
{
    u_char      ch, *p, *c;
    ngx_str_t  *arg;
    enum {
        sw_start = 0,
        sw_spaces_before_command,
        sw_command,
        sw_spaces_before_argument,
        sw_argument,
        sw_backslash,
        sw_literal,
        sw_no_sync_literal_argument,
        sw_start_literal_argument,
        sw_literal_argument,
        sw_end_literal_argument,
        sw_almost_done
    } state;

    state = s->state;

    for (p = s->buffer->pos; p < s->buffer->last; p++) {
        ch = *p;

        switch (state) {

        /* IMAP tag */
        case sw_start:
            switch (ch) {
            case ' ':
                s->tag.len = p - s->buffer->start + 1;
                s->tag.data = s->buffer->start;
                state = sw_spaces_before_command;
                break;
            case CR:
                s->state = sw_start;
                return NGX_MAIL_PARSE_INVALID_COMMAND;
            case LF:
                s->state = sw_start;
                return NGX_MAIL_PARSE_INVALID_COMMAND;
            }
            break;

        case sw_spaces_before_command:
            switch (ch) {
            case ' ':
                break;
            case CR:
                s->state = sw_start;
                return NGX_MAIL_PARSE_INVALID_COMMAND;
            case LF:
                s->state = sw_start;
                return NGX_MAIL_PARSE_INVALID_COMMAND;
            default:
                s->cmd_start = p;
                state = sw_command;
                break;
            }
            break;

        case sw_command:
            if (ch == ' ' || ch == CR || ch == LF) {

                c = s->cmd_start;

                switch (p - c) {

                case 4:
                    if ((c[0] == 'N' || c[0] == 'n')
                        && (c[1] == 'O'|| c[1] == 'o')
                        && (c[2] == 'O'|| c[2] == 'o')
                        && (c[3] == 'P'|| c[3] == 'p'))
                    {
                        s->command = NGX_IMAP_NOOP;

                    } else {
                        goto invalid;
                    }
                    break;

                case 5:
                    if ((c[0] == 'L'|| c[0] == 'l')
                        && (c[1] == 'O'|| c[1] == 'o')
                        && (c[2] == 'G'|| c[2] == 'g')
                        && (c[3] == 'I'|| c[3] == 'i')
                        && (c[4] == 'N'|| c[4] == 'n'))
                    {
                        s->command = NGX_IMAP_LOGIN;

                    } else {
                        goto invalid;
                    }
                    break;

                case 6:
                    if ((c[0] == 'L'|| c[0] == 'l')
                        && (c[1] == 'O'|| c[1] == 'o')
                        && (c[2] == 'G'|| c[2] == 'g')
                        && (c[3] == 'O'|| c[3] == 'o')
                        && (c[4] == 'U'|| c[4] == 'u')
                        && (c[5] == 'T'|| c[5] == 't'))
                    {
                        s->command = NGX_IMAP_LOGOUT;

                    } else {
                        goto invalid;
                    }
                    break;

#if (NGX_MAIL_SSL)
                case 8:
                    if ((c[0] == 'S'|| c[0] == 's')
                        && (c[1] == 'T'|| c[1] == 't')
                        && (c[2] == 'A'|| c[2] == 'a')
                        && (c[3] == 'R'|| c[3] == 'r')
                        && (c[4] == 'T'|| c[4] == 't')
                        && (c[5] == 'T'|| c[5] == 't')
                        && (c[6] == 'L'|| c[6] == 'l')
                        && (c[7] == 'S'|| c[7] == 's'))
                    {
                        s->command = NGX_IMAP_STARTTLS;

                    } else {
                        goto invalid;
                    }
                    break;
#endif

                case 10:
                    if ((c[0] == 'C'|| c[0] == 'c')
                        && (c[1] == 'A'|| c[1] == 'a')
                        && (c[2] == 'P'|| c[2] == 'p')
                        && (c[3] == 'A'|| c[3] == 'a')
                        && (c[4] == 'B'|| c[4] == 'b')
                        && (c[5] == 'I'|| c[5] == 'i')
                        && (c[6] == 'L'|| c[6] == 'l')
                        && (c[7] == 'I'|| c[7] == 'i')
                        && (c[8] == 'T'|| c[8] == 't')
                        && (c[9] == 'Y'|| c[9] == 'y'))
                    {
                        s->command = NGX_IMAP_CAPABILITY;

                    } else {
                        goto invalid;
                    }
                    break;

                case 12:
                    if ((c[0] == 'A'|| c[0] == 'a')
                        && (c[1] == 'U'|| c[1] == 'u')
                        && (c[2] == 'T'|| c[2] == 't')
                        && (c[3] == 'H'|| c[3] == 'h')
                        && (c[4] == 'E'|| c[4] == 'e')
                        && (c[5] == 'N'|| c[5] == 'n')
                        && (c[6] == 'T'|| c[6] == 't')
                        && (c[7] == 'I'|| c[7] == 'i')
                        && (c[8] == 'C'|| c[8] == 'c')
                        && (c[9] == 'A'|| c[9] == 'a')
                        && (c[10] == 'T'|| c[10] == 't')
                        && (c[11] == 'E'|| c[11] == 'e'))
                    {
                        s->command = NGX_IMAP_AUTHENTICATE;

                    } else {
                        goto invalid;
                    }
                    break;

                default:
                    goto invalid;
                }

                switch (ch) {
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;
            }

            if ((ch < 'A' || ch > 'Z') && (ch < 'a' || ch > 'z')) {
                goto invalid;
            }

            break;

        case sw_spaces_before_argument:
            switch (ch) {
            case ' ':
                break;
            case CR:
                state = sw_almost_done;
                s->arg_end = p;
                break;
            case LF:
                s->arg_end = p;
                goto done;
            case '"':
                if (s->args.nelts <= 2) {
                    s->quoted = 1;
                    s->arg_start = p + 1;
                    state = sw_argument;
                    break;
                }
                goto invalid;
            case '{':
                if (s->args.nelts <= 2) {
                    state = sw_literal;
                    break;
                }
                goto invalid;
            default:
                if (s->args.nelts <= 2) {
                    s->arg_start = p;
                    state = sw_argument;
                    break;
                }
                goto invalid;
            }
            break;

        case sw_argument:
            if (ch == ' ' && s->quoted) {
                break;
            }

            switch (ch) {
            case '"':
                if (!s->quoted) {
                    break;
                }
                s->quoted = 0;
                /* fall through */
            case ' ':
            case CR:
            case LF:
                arg = ngx_array_push(&s->args);
                if (arg == NULL) {
                    return NGX_ERROR;
                }
                arg->len = p - s->arg_start;
                arg->data = s->arg_start;
                s->arg_start = NULL;

                switch (ch) {
                case '"':
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;
            case '\\':
                if (s->quoted) {
                    s->backslash = 1;
                    state = sw_backslash;
                }
                break;
            }
            break;

        case sw_backslash:
            switch (ch) {
            case CR:
            case LF:
                goto invalid;
            default:
                state = sw_argument;
            }
            break;

        case sw_literal:
            if (ch >= '0' && ch <= '9') {
                s->literal_len = s->literal_len * 10 + (ch - '0');
                break;
            }
            if (ch == '}') {
                state = sw_start_literal_argument;
                break;
            }
            if (ch == '+') {
                state = sw_no_sync_literal_argument;
                break;
            }
            goto invalid;

        case sw_no_sync_literal_argument:
            if (ch == '}') {
                s->no_sync_literal = 1;
                state = sw_start_literal_argument;
                break;
            }
            goto invalid;

        case sw_start_literal_argument:
            switch (ch) {
            case CR:
                break;
            case LF:
                s->buffer->pos = p + 1;
                s->arg_start = p + 1;
                if (s->no_sync_literal == 0) {
                    s->state = sw_literal_argument;
                    return NGX_IMAP_NEXT;
                }
                state = sw_literal_argument;
                s->no_sync_literal = 0;
                break;
            default:
                goto invalid;
            }
            break;

        case sw_literal_argument:
            if (s->literal_len && --s->literal_len) {
                break;
            }

            arg = ngx_array_push(&s->args);
            if (arg == NULL) {
                return NGX_ERROR;
            }
            arg->len = p + 1 - s->arg_start;
            arg->data = s->arg_start;
            s->arg_start = NULL;
            state = sw_end_literal_argument;

            break;

        case sw_end_literal_argument:
            switch (ch) {
            case '{':
                if (s->args.nelts <= 2) {
                    state = sw_literal;
                    break;
                }
                goto invalid;
            case CR:
                state = sw_almost_done;
                break;
            case LF:
                goto done;
            default:
                state = sw_spaces_before_argument;
                break;
            }
            break;

        case sw_almost_done:
            switch (ch) {
            case LF:
                goto done;
            default:
                goto invalid;
            }
        }
    }

    s->buffer->pos = p;
    s->state = state;

    return NGX_AGAIN;

done:

    s->buffer->pos = p + 1;

    if (s->arg_start) {
        arg = ngx_array_push(&s->args);
        if (arg == NULL) {
            return NGX_ERROR;
        }
        arg->len = s->arg_end - s->arg_start;
        arg->data = s->arg_start;

        s->arg_start = NULL;
        s->cmd_start = NULL;
        s->quoted = 0;
        s->no_sync_literal = 0;
        s->literal_len = 0;
    }

    s->state = (s->command != NGX_IMAP_AUTHENTICATE) ? sw_start : sw_argument;

    return NGX_OK;

invalid:

    s->state = sw_start;
    s->quoted = 0;
    s->no_sync_literal = 0;
    s->literal_len = 0;

    return NGX_MAIL_PARSE_INVALID_COMMAND;
}


ngx_int_t
ngx_mail_smtp_parse_command(ngx_mail_session_t *s)
{
    u_char      ch, *p, *c, c0, c1, c2, c3;
    ngx_str_t  *arg;
    enum {
        sw_start = 0,
        sw_command,
        sw_invalid,
        sw_spaces_before_argument,
        sw_argument,
        sw_almost_done
    } state;

    state = s->state;

    for (p = s->buffer->pos; p < s->buffer->last; p++) {
        ch = *p;

        switch (state) {

        /* SMTP command */
        case sw_start:
            s->cmd_start = p;
            state = sw_command;

            /* fall through */

        case sw_command:
            if (ch == ' ' || ch == CR || ch == LF) {
                c = s->cmd_start;

                if (p - c == 4) {

                    c0 = ngx_toupper(c[0]);
                    c1 = ngx_toupper(c[1]);
                    c2 = ngx_toupper(c[2]);
                    c3 = ngx_toupper(c[3]);

                    if (c0 == 'H' && c1 == 'E' && c2 == 'L' && c3 == 'O')
                    {
                        s->command = NGX_SMTP_HELO;

                    } else if (c0 == 'E' && c1 == 'H' && c2 == 'L' && c3 == 'O')
                    {
                        s->command = NGX_SMTP_EHLO;

                    } else if (c0 == 'Q' && c1 == 'U' && c2 == 'I' && c3 == 'T')
                    {
                        s->command = NGX_SMTP_QUIT;

                    } else if (c0 == 'A' && c1 == 'U' && c2 == 'T' && c3 == 'H')
                    {
                        s->command = NGX_SMTP_AUTH;

                    } else if (c0 == 'N' && c1 == 'O' && c2 == 'O' && c3 == 'P')
                    {
                        s->command = NGX_SMTP_NOOP;

                    } else if (c0 == 'M' && c1 == 'A' && c2 == 'I' && c3 == 'L')
                    {
                        s->command = NGX_SMTP_MAIL;

                    } else if (c0 == 'R' && c1 == 'S' && c2 == 'E' && c3 == 'T')
                    {
                        s->command = NGX_SMTP_RSET;

                    } else if (c0 == 'R' && c1 == 'C' && c2 == 'P' && c3 == 'T')
                    {
                        s->command = NGX_SMTP_RCPT;

                    } else if (c0 == 'V' && c1 == 'R' && c2 == 'F' && c3 == 'Y')
                    {
                        s->command = NGX_SMTP_VRFY;

                    } else if (c0 == 'E' && c1 == 'X' && c2 == 'P' && c3 == 'N')
                    {
                        s->command = NGX_SMTP_EXPN;

                    } else if (c0 == 'H' && c1 == 'E' && c2 == 'L' && c3 == 'P')
                    {
                        s->command = NGX_SMTP_HELP;

                    } else {
                        goto invalid;
                    }
#if (NGX_MAIL_SSL)
                } else if (p - c == 8) {

                    if ((c[0] == 'S'|| c[0] == 's')
                        && (c[1] == 'T'|| c[1] == 't')
                        && (c[2] == 'A'|| c[2] == 'a')
                        && (c[3] == 'R'|| c[3] == 'r')
                        && (c[4] == 'T'|| c[4] == 't')
                        && (c[5] == 'T'|| c[5] == 't')
                        && (c[6] == 'L'|| c[6] == 'l')
                        && (c[7] == 'S'|| c[7] == 's'))
                    {
                        s->command = NGX_SMTP_STARTTLS;

                    } else {
                        goto invalid;
                    }
#endif
                } else {
                    goto invalid;
                }

                s->cmd.data = s->cmd_start;
                s->cmd.len = p - s->cmd_start;

                switch (ch) {
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;
            }

            if ((ch < 'A' || ch > 'Z') && (ch < 'a' || ch > 'z')) {
                goto invalid;
            }

            break;

        case sw_invalid:
            goto invalid;

        case sw_spaces_before_argument:
            switch (ch) {
            case ' ':
                break;
            case CR:
                state = sw_almost_done;
                s->arg_end = p;
                break;
            case LF:
                s->arg_end = p;
                goto done;
            default:
                if (s->args.nelts <= 10) {
                    state = sw_argument;
                    s->arg_start = p;
                    break;
                }
                goto invalid;
            }
            break;

        case sw_argument:
            switch (ch) {
            case ' ':
            case CR:
            case LF:
                arg = ngx_array_push(&s->args);
                if (arg == NULL) {
                    return NGX_ERROR;
                }
                arg->len = p - s->arg_start;
                arg->data = s->arg_start;
                s->arg_start = NULL;

                switch (ch) {
                case ' ':
                    state = sw_spaces_before_argument;
                    break;
                case CR:
                    state = sw_almost_done;
                    break;
                case LF:
                    goto done;
                }
                break;

            default:
                break;
            }
            break;

        case sw_almost_done:
            switch (ch) {
            case LF:
                goto done;
            default:
                goto invalid;
            }
        }
    }

    s->buffer->pos = p;
    s->state = state;

    return NGX_AGAIN;

done:

    s->buffer->pos = p + 1;

    if (s->arg_start) {
        arg = ngx_array_push(&s->args);
        if (arg == NULL) {
            return NGX_ERROR;
        }
        arg->len = s->arg_end - s->arg_start;
        arg->data = s->arg_start;
        s->arg_start = NULL;
    }

    s->state = (s->command != NGX_SMTP_AUTH) ? sw_start : sw_argument;

    return NGX_OK;

invalid:

    s->state = sw_invalid;
    s->arg_start = NULL;

    /* skip invalid command till LF */

    for (p = s->buffer->pos; p < s->buffer->last; p++) {
        if (*p == LF) {
            s->state = sw_start;
            p++;
            break;
        }
    }

    s->buffer->pos = p;

    return NGX_MAIL_PARSE_INVALID_COMMAND;
}


ngx_int_t
ngx_mail_auth_parse(ngx_mail_session_t *s, ngx_connection_t *c)
{
    ngx_str_t                 *arg;

#if (NGX_MAIL_SSL)
    if (ngx_mail_starttls_only(s, c)) {
        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }
#endif

    if (s->args.nelts == 0) {
        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }

    arg = s->args.elts;

    if (arg[0].len == 5) {

        if (ngx_strncasecmp(arg[0].data, (u_char *) "LOGIN", 5) == 0) {

            if (s->args.nelts == 1) {
                return NGX_MAIL_AUTH_LOGIN;
            }

            if (s->args.nelts == 2) {
                return NGX_MAIL_AUTH_LOGIN_USERNAME;
            }

            return NGX_MAIL_PARSE_INVALID_COMMAND;
        }

        if (ngx_strncasecmp(arg[0].data, (u_char *) "PLAIN", 5) == 0) {

            if (s->args.nelts == 1) {
                return NGX_MAIL_AUTH_PLAIN;
            }

            if (s->args.nelts == 2) {
                return ngx_mail_auth_plain(s, c, 1);
            }
        }

        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }

    if (arg[0].len == 8) {

        if (ngx_strncasecmp(arg[0].data, (u_char *) "CRAM-MD5", 8) == 0) {

            if (s->args.nelts != 1) {
                return NGX_MAIL_PARSE_INVALID_COMMAND;
            }

            return NGX_MAIL_AUTH_CRAM_MD5;
        }

        if (ngx_strncasecmp(arg[0].data, (u_char *) "EXTERNAL", 8) == 0) {

            if (s->args.nelts == 1) {
                return NGX_MAIL_AUTH_EXTERNAL;
            }

            if (s->args.nelts == 2) {
                return ngx_mail_auth_external(s, c, 1);
            }
        }

        return NGX_MAIL_PARSE_INVALID_COMMAND;
    }

    return NGX_MAIL_PARSE_INVALID_COMMAND;
}