Mercurial > hg > nginx
view src/core/ngx_bpf.c @ 9112:d59277dd3d8c
QUIC: fixed post-close use-after-free.
Previously, ngx_quic_close_connection() could be called in a way that QUIC
connection was accessed after the call. In most cases the connection is not
closed right away, but close timeout is scheduled. However, it's not always
the case. Also, if the close process started earlier for a different reason,
calling ngx_quic_close_connection() may actually close the connection. The
connection object should not be accessed after that.
Now, when possible, return statement is added to eliminate post-close connection
object access. In other places ngx_quic_close_connection() is substituted with
posting close event.
Also, the new way of closing connection in ngx_quic_stream_cleanup_handler()
fixes another problem in this function. Previously it passed stream connection
instead of QUIC connection to ngx_quic_close_connection(). This could result
in incomplete connection shutdown. One consequence of that could be that QUIC
streams were freed without shutting down their application contexts. This could
result in another use-after-free.
Found by Coverity (CID 1530402).
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Mon, 22 May 2023 15:59:42 +0400 |
parents | 7a07724256c2 |
children |
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/* * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #define NGX_BPF_LOGBUF_SIZE (16 * 1024) static ngx_inline int ngx_bpf(enum bpf_cmd cmd, union bpf_attr *attr, unsigned int size) { return syscall(__NR_bpf, cmd, attr, size); } void ngx_bpf_program_link(ngx_bpf_program_t *program, const char *symbol, int fd) { ngx_uint_t i; ngx_bpf_reloc_t *rl; rl = program->relocs; for (i = 0; i < program->nrelocs; i++) { if (ngx_strcmp(rl[i].name, symbol) == 0) { program->ins[rl[i].offset].src_reg = 1; program->ins[rl[i].offset].imm = fd; } } } int ngx_bpf_load_program(ngx_log_t *log, ngx_bpf_program_t *program) { int fd; union bpf_attr attr; #if (NGX_DEBUG) char buf[NGX_BPF_LOGBUF_SIZE]; #endif ngx_memzero(&attr, sizeof(union bpf_attr)); attr.license = (uintptr_t) program->license; attr.prog_type = program->type; attr.insns = (uintptr_t) program->ins; attr.insn_cnt = program->nins; #if (NGX_DEBUG) /* for verifier errors */ attr.log_buf = (uintptr_t) buf; attr.log_size = NGX_BPF_LOGBUF_SIZE; attr.log_level = 1; #endif fd = ngx_bpf(BPF_PROG_LOAD, &attr, sizeof(attr)); if (fd < 0) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "failed to load BPF program"); ngx_log_debug1(NGX_LOG_DEBUG_CORE, log, 0, "bpf verifier: %s", buf); return -1; } return fd; } int ngx_bpf_map_create(ngx_log_t *log, enum bpf_map_type type, int key_size, int value_size, int max_entries, uint32_t map_flags) { int fd; union bpf_attr attr; ngx_memzero(&attr, sizeof(union bpf_attr)); attr.map_type = type; attr.key_size = key_size; attr.value_size = value_size; attr.max_entries = max_entries; attr.map_flags = map_flags; fd = ngx_bpf(BPF_MAP_CREATE, &attr, sizeof(attr)); if (fd < 0) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "failed to create BPF map"); return NGX_ERROR; } return fd; } int ngx_bpf_map_update(int fd, const void *key, const void *value, uint64_t flags) { union bpf_attr attr; ngx_memzero(&attr, sizeof(union bpf_attr)); attr.map_fd = fd; attr.key = (uintptr_t) key; attr.value = (uintptr_t) value; attr.flags = flags; return ngx_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr)); } int ngx_bpf_map_delete(int fd, const void *key) { union bpf_attr attr; ngx_memzero(&attr, sizeof(union bpf_attr)); attr.map_fd = fd; attr.key = (uintptr_t) key; return ngx_bpf(BPF_MAP_DELETE_ELEM, &attr, sizeof(attr)); } int ngx_bpf_map_lookup(int fd, const void *key, void *value) { union bpf_attr attr; ngx_memzero(&attr, sizeof(union bpf_attr)); attr.map_fd = fd; attr.key = (uintptr_t) key; attr.value = (uintptr_t) value; return ngx_bpf(BPF_MAP_LOOKUP_ELEM, &attr, sizeof(attr)); }