Mercurial > hg > nginx-quic
view auto/os/linux @ 8460:3974f4e56a4e
Mail: fixed s->arg_start clearing on invalid IMAP commands.
Previously, s->arg_start was left intact after invalid IMAP commands,
and this might result in an argument incorrectly added to the following
command. Similarly, s->backslash was left intact as well, leading
to unneeded backslash removal.
For example (LFs from the client are explicitly shown as "<LF>"):
S: * OK IMAP4 ready
C: a01 login "\<LF>
S: a01 BAD invalid command
C: a0000000000\2 authenticate <LF>
S: a00000000002 aBAD invalid command
The backslash followed by LF generates invalid command with s->arg_start
and s->backslash set, the following command incorrectly treats anything
from the old s->arg_start to the space after the command as an argument,
and removes the backslash from the tag. If there is no space, s->arg_end
will be NULL.
Both things seem to be harmless though. In particular:
- This can be used to provide an incorrect argument to a command without
arguments. The only command which seems to look at the single argument
is AUTHENTICATE, and it checks the argument length before trying to
access it.
- Backslash removal uses the "end" pointer, and stops due to "src < end"
condition instead of scanning all the process memory if s->arg_end is
NULL (and arg[0].len is huge).
- There should be no backslashes in unquoted strings.
An obvious fix is to clear s->arg_start and s->backslash on invalid commands,
similarly to how it is done in POP3 parsing (added in 810:e3aa8f305d21) and
SMTP parsing.
This, however, makes it clear that s->arg_start handling in the "done"
label is wrong: s->arg_start cannot be legitimately set there, as it
is expected to be cleared in all possible cases when the "done" label is
reached. The relevant code is dead and will be removed by the following
change.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 19 May 2021 03:13:20 +0300 |
parents | e2e9e0fae747 |
children | 7f95010f10b7 c0a432c0301b |
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# Copyright (C) Igor Sysoev # Copyright (C) Nginx, Inc. have=NGX_LINUX . auto/have_headers CORE_INCS="$UNIX_INCS" CORE_DEPS="$UNIX_DEPS $LINUX_DEPS" CORE_SRCS="$UNIX_SRCS $LINUX_SRCS" ngx_spacer=' ' cc_aux_flags="$CC_AUX_FLAGS" CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64" # Linux kernel version version=$((`uname -r \ | sed -n -e 's/^\([0-9][0-9]*\)\.\([0-9][0-9]*\)\.\([0-9][0-9]*\).*/ \ \1*256*256+\2*256+\3/p' \ -e 's/^\([0-9][0-9]*\)\.\([0-9][0-9]*\).*/\1*256*256+\2*256/p'`)) version=${version:-0} # posix_fadvise64() had been implemented in 2.5.60 if [ $version -lt 132412 ]; then have=NGX_HAVE_POSIX_FADVISE . auto/nohave fi # epoll, EPOLLET version ngx_feature="epoll" ngx_feature_name="NGX_HAVE_EPOLL" ngx_feature_run=yes ngx_feature_incs="#include <sys/epoll.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int efd = 0; struct epoll_event ee; ee.events = EPOLLIN|EPOLLOUT|EPOLLET; ee.data.ptr = NULL; (void) ee; efd = epoll_create(100); if (efd == -1) return 1;" . auto/feature if [ $ngx_found = yes ]; then have=NGX_HAVE_CLEAR_EVENT . auto/have CORE_SRCS="$CORE_SRCS $EPOLL_SRCS" EVENT_MODULES="$EVENT_MODULES $EPOLL_MODULE" EVENT_FOUND=YES # EPOLLRDHUP appeared in Linux 2.6.17, glibc 2.8 ngx_feature="EPOLLRDHUP" ngx_feature_name="NGX_HAVE_EPOLLRDHUP" ngx_feature_run=no ngx_feature_incs="#include <sys/epoll.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int efd = 0, fd = 0; struct epoll_event ee; ee.events = EPOLLIN|EPOLLRDHUP|EPOLLET; ee.data.ptr = NULL; epoll_ctl(efd, EPOLL_CTL_ADD, fd, &ee)" . auto/feature # EPOLLEXCLUSIVE appeared in Linux 4.5, glibc 2.24 ngx_feature="EPOLLEXCLUSIVE" ngx_feature_name="NGX_HAVE_EPOLLEXCLUSIVE" ngx_feature_run=no ngx_feature_incs="#include <sys/epoll.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int efd = 0, fd = 0; struct epoll_event ee; ee.events = EPOLLIN|EPOLLEXCLUSIVE; ee.data.ptr = NULL; epoll_ctl(efd, EPOLL_CTL_ADD, fd, &ee)" . auto/feature # eventfd() ngx_feature="eventfd()" ngx_feature_name="NGX_HAVE_EVENTFD" ngx_feature_run=no ngx_feature_incs="#include <sys/eventfd.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="(void) eventfd(0, 0)" . auto/feature if [ $ngx_found = yes ]; then have=NGX_HAVE_SYS_EVENTFD_H . auto/have fi if [ $ngx_found = no ]; then ngx_feature="eventfd() (SYS_eventfd)" ngx_feature_incs="#include <sys/syscall.h>" ngx_feature_test="(void) SYS_eventfd" . auto/feature fi fi # O_PATH and AT_EMPTY_PATH were introduced in 2.6.39, glibc 2.14 ngx_feature="O_PATH" ngx_feature_name="NGX_HAVE_O_PATH" ngx_feature_run=no ngx_feature_incs="#include <sys/types.h> #include <sys/stat.h> #include <fcntl.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int fd; struct stat sb; fd = openat(AT_FDCWD, \".\", O_PATH|O_DIRECTORY|O_NOFOLLOW); if (fstatat(fd, \"\", &sb, AT_EMPTY_PATH) != 0) return 1" . auto/feature # sendfile() CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE" ngx_feature="sendfile()" ngx_feature_name="NGX_HAVE_SENDFILE" ngx_feature_run=yes ngx_feature_incs="#include <sys/sendfile.h> #include <errno.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int s = 0, fd = 1; ssize_t n; off_t off = 0; n = sendfile(s, fd, &off, 1); if (n == -1 && errno == ENOSYS) return 1" . auto/feature if [ $ngx_found = yes ]; then CORE_SRCS="$CORE_SRCS $LINUX_SENDFILE_SRCS" fi # sendfile64() CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64" ngx_feature="sendfile64()" ngx_feature_name="NGX_HAVE_SENDFILE64" ngx_feature_run=yes ngx_feature_incs="#include <sys/sendfile.h> #include <errno.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="int s = 0, fd = 1; ssize_t n; off_t off = 0; n = sendfile(s, fd, &off, 1); if (n == -1 && errno == ENOSYS) return 1" . auto/feature ngx_include="sys/prctl.h"; . auto/include # prctl(PR_SET_DUMPABLE) ngx_feature="prctl(PR_SET_DUMPABLE)" ngx_feature_name="NGX_HAVE_PR_SET_DUMPABLE" ngx_feature_run=yes ngx_feature_incs="#include <sys/prctl.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="if (prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) == -1) return 1" . auto/feature # prctl(PR_SET_KEEPCAPS) ngx_feature="prctl(PR_SET_KEEPCAPS)" ngx_feature_name="NGX_HAVE_PR_SET_KEEPCAPS" ngx_feature_run=yes ngx_feature_incs="#include <sys/prctl.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) == -1) return 1" . auto/feature # capabilities ngx_feature="capabilities" ngx_feature_name="NGX_HAVE_CAPABILITIES" ngx_feature_run=no ngx_feature_incs="#include <linux/capability.h> #include <sys/syscall.h>" ngx_feature_path= ngx_feature_libs= ngx_feature_test="struct __user_cap_data_struct data; struct __user_cap_header_struct header; header.version = _LINUX_CAPABILITY_VERSION_1; data.effective = CAP_TO_MASK(CAP_NET_RAW); data.permitted = 0; (void) header; (void) data; (void) SYS_capset" . auto/feature # crypt_r() ngx_feature="crypt_r()" ngx_feature_name="NGX_HAVE_GNU_CRYPT_R" ngx_feature_run=no ngx_feature_incs="#include <crypt.h>" ngx_feature_path= ngx_feature_libs=-lcrypt ngx_feature_test="struct crypt_data cd; crypt_r(\"key\", \"salt\", &cd);" . auto/feature ngx_include="sys/vfs.h"; . auto/include CC_AUX_FLAGS="$cc_aux_flags -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64"