From dcee489f821c1260a0136fcdfdb6ff4dd11086ac Mon Sep 17 00:00:00 2001 From: Alexander Kanavin Date: Wed, 9 Dec 2015 17:58:03 +0200 Subject: [PATCH] Fix CVE-2015-1197 Apply patch by Vitezslav Cizek of SuSE to fix CVE-2015-1197. Upstream is dormant or no longer existing. To restore the old behaviour use --extract-over-symlinks (Closes: #774669) This issue has been discovered by Alexander Cherepanov. Author: Vitezslav Cizek Bug-Debian: https://bugs.debian.org/774669 Upstream-Status: Pending CVE: CVE-2015-1197 Signed-off-by: Robert Yang Signed-off-by: Alexander Kanavin --- doc/cpio.1 | 1 + src/copyin.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ src/extern.h | 1 + src/global.c | 3 +++ src/main.c | 7 +++++++ 5 files changed, 74 insertions(+) diff --git a/doc/cpio.1 b/doc/cpio.1 index 2a68241..dc4676c 100644 --- a/doc/cpio.1 +++ b/doc/cpio.1 @@ -49,6 +49,7 @@ cpio \- copy files to and from archives [\fB\-\-no\-preserve\-owner\fR] [\fB\-\-message=\fIMESSAGE\fR] [\fB\-\-force\-local\fR] [\fB\-\-no\-absolute\-filenames\fR] [\fB\-\-sparse\fR] [\fB\-\-only\-verify\-crc\fR] [\fB\-\-to\-stdout\fR] [\fB\-\-quiet\fR] +[\fB\-\-extract\-over\-symlinks\fR] [\fB\-\-rsh\-command=\fICOMMAND\fR] [\fIpattern\fR...] [\fB<\fR \fIarchive\fR] diff --git a/src/copyin.c b/src/copyin.c index cde911e..053afe7 100644 --- a/src/copyin.c +++ b/src/copyin.c @@ -695,6 +695,51 @@ copyin_link (struct cpio_file_stat *file_hdr, int in_file_des) free (link_name); } + +static int +path_contains_symlink(char *path) +{ + struct stat st; + char *slash; + char *nextslash; + + /* we got NULL pointer or empty string */ + if (!path || !*path) { + return false; + } + + slash = path; + + while ((nextslash = strchr(slash + 1, '/')) != NULL) { + slash = nextslash; + *slash = '\0'; + + if (lstat(path, &st) != 0) { + if (errno == ELOOP) { + /* ELOOP - too many symlinks */ + *slash = '/'; + return true; + } else if (errno == ENOMEM) { + /* No memory for lstat - terminate */ + xalloc_die(); + } else { + /* cannot lstat path - give up */ + *slash = '/'; + return false; + } + } + + if (S_ISLNK(st.st_mode)) { + *slash = '/'; + return true; + } + + *slash = '/'; + } + + return false; +} + static void copyin_file (struct cpio_file_stat *file_hdr, int in_file_des) { @@ -1468,6 +1513,23 @@ process_copy_in () { /* Copy the input file into the directory structure. */ + /* Can we write files over symlinks? */ + if (!extract_over_symlinks) + { + if (path_contains_symlink(file_hdr.c_name)) + { + /* skip the file */ + /* + fprintf(stderr, "Can't write over symlinks. Skipping %s\n", file_hdr.c_name); + tape_toss_input (in_file_des, file_hdr.c_filesize); + tape_skip_padding (in_file_des, file_hdr.c_filesize); + continue; + */ + /* terminate */ + error (1, 0, _("Can't write over symlinks: %s\n"), file_hdr.c_name); + } + } + /* Do we need to rename the file? */ if (rename_flag || rename_batch_file) { diff --git a/src/extern.h b/src/extern.h index e27d662..d864bde 100644 --- a/src/extern.h +++ b/src/extern.h @@ -96,6 +96,7 @@ extern char input_is_special; extern char output_is_special; extern char input_is_seekable; extern char output_is_seekable; +extern bool extract_over_symlinks; extern int (*xstat) (); extern void (*copy_function) (); extern char *change_directory_option; diff --git a/src/global.c b/src/global.c index 57e505a..336fce4 100644 --- a/src/global.c +++ b/src/global.c @@ -187,6 +187,9 @@ bool to_stdout_option = false; /* The name this program was run with. */ char *program_name; +/* Extract files over symbolic links */ +bool extract_over_symlinks; + /* A pointer to either lstat or stat, depending on whether dereferencing of symlinks is done for input files. */ int (*xstat) (); diff --git a/src/main.c b/src/main.c index a13861f..87cb309 100644 --- a/src/main.c +++ b/src/main.c @@ -59,6 +59,7 @@ enum cpio_options { DEBUG_OPTION, BLOCK_SIZE_OPTION, TO_STDOUT_OPTION, + EXTRACT_OVER_SYMLINKS, RENUMBER_INODES_OPTION, IGNORE_DEVNO_OPTION, DEVICE_INDEPENDENT_OPTION @@ -243,6 +244,8 @@ static struct argp_option options[] = { N_("Create leading directories where needed"), GRID+1 }, {"no-preserve-owner", NO_PRESERVE_OWNER_OPTION, 0, 0, N_("Do not change the ownership of the files"), GRID+1 }, + {"extract-over-symlinks", EXTRACT_OVER_SYMLINKS, 0, 0, + N_("Force writing over symbolic links"), GRID+1 }, {"unconditional", 'u', NULL, 0, N_("Replace all files unconditionally"), GRID+1 }, {"sparse", SPARSE_OPTION, NULL, 0, @@ -432,6 +435,10 @@ crc newc odc bin ustar tar (all-caps also recognized)"), arg)); no_chown_flag = true; break; + case EXTRACT_OVER_SYMLINKS: /* --extract-over-symlinks */ + extract_over_symlinks = true; + break; + case 'o': /* Copy-out mode. */ if (copy_function != 0) USAGE_ERROR ((0, 0, _("Mode already defined"))); -- 2.6.2