diff options
Diffstat (limited to 'src/core/ngx_open_file_cache.c')
| -rw-r--r-- | src/core/ngx_open_file_cache.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/src/core/ngx_open_file_cache.c b/src/core/ngx_open_file_cache.c index b72af5ea0..e5773ac0d 100644 --- a/src/core/ngx_open_file_cache.c +++ b/src/core/ngx_open_file_cache.c @@ -25,6 +25,10 @@ static void ngx_open_file_cache_cleanup(void *data); #if (NGX_HAVE_OPENAT) static ngx_fd_t ngx_openat_file_owner(ngx_fd_t at_fd, const u_char *name, ngx_int_t mode, ngx_int_t create, ngx_int_t access, ngx_log_t *log); +#if (NGX_HAVE_O_PATH) +static ngx_int_t ngx_file_o_path_info(ngx_fd_t fd, ngx_file_info_t *fi, + ngx_log_t *log); +#endif #endif static ngx_fd_t ngx_open_file_wrapper(ngx_str_t *name, ngx_open_file_info_t *of, ngx_int_t mode, ngx_int_t create, @@ -517,10 +521,17 @@ ngx_openat_file_owner(ngx_fd_t at_fd, const u_char *name, goto failed; } +#if (NGX_HAVE_O_PATH) + if (ngx_file_o_path_info(fd, &fi, log) == NGX_ERROR) { + err = ngx_errno; + goto failed; + } +#else if (ngx_fd_info(fd, &fi) == NGX_FILE_ERROR) { err = ngx_errno; goto failed; } +#endif if (fi.st_uid != atfi.st_uid) { err = NGX_ELOOP; @@ -541,8 +552,64 @@ failed: return NGX_INVALID_FILE; } + +#if (NGX_HAVE_O_PATH) + +static ngx_int_t +ngx_file_o_path_info(ngx_fd_t fd, ngx_file_info_t *fi, ngx_log_t *log) +{ + static ngx_uint_t use_fstat = 1; + + /* + * In Linux 2.6.39 the O_PATH flag was introduced that allows to obtain + * a descriptor without actually opening file or directory. It requires + * less permissions for path components, but till Linux 3.6 fstat() returns + * EBADF on such descriptors, and fstatat() with the AT_EMPTY_PATH flag + * should be used instead. + * + * Three scenarios are handled in this function: + * + * 1) The kernel is newer than 3.6 or fstat() with O_PATH support was + * backported by vendor. Then fstat() is used. + * + * 2) The kernel is newer than 2.6.39 but older than 3.6. In this case + * the first call of fstat() returns EBADF and we fallback to fstatat() + * with AT_EMPTY_PATH which was introduced at the same time as O_PATH. + * + * 3) The kernel is older than 2.6.39 but nginx was build with O_PATH + * support. Since descriptors are opened with O_PATH|O_RDONLY flags + * and O_PATH is ignored by the kernel then the O_RDONLY flag is + * actually used. In this case fstat() just works. + */ + + if (use_fstat) { + if (ngx_fd_info(fd, fi) != NGX_FILE_ERROR) { + return NGX_OK; + } + + if (ngx_errno != NGX_EBADF) { + return NGX_ERROR; + } + + ngx_log_error(NGX_LOG_NOTICE, log, 0, + "fstat(O_PATH) failed with EBADF, " + "switching to fstatat(AT_EMPTY_PATH)"); + + use_fstat = 0; + return ngx_file_o_path_info(fd, fi, log); + } + + if (ngx_file_at_info(fd, "", fi, AT_EMPTY_PATH) != NGX_FILE_ERROR) { + return NGX_OK; + } + + return NGX_ERROR; +} + #endif +#endif /* NGX_HAVE_OPENAT */ + static ngx_fd_t ngx_open_file_wrapper(ngx_str_t *name, ngx_open_file_info_t *of, |