diff options
author | Denys Vlasenko <vda.linux@googlemail.com> | 2015-02-10 03:30:43 +0300 |
---|---|---|
committer | Denys Vlasenko <vda.linux@googlemail.com> | 2015-02-10 03:30:43 +0300 |
commit | 8c06bc6ba14949d945eff0abcabab885f1ef7680 (patch) | |
tree | 438b36b8264a1b257d4fb3e6293dcda1a4ac9d35 /archival | |
parent | 23cfaab47de7392c1ba7d601a05fb36da3629b28 (diff) |
unzip: prevent attacks via malicious filenames
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'archival')
-rw-r--r-- | archival/libarchive/Kbuild.src | 5 | ||||
-rw-r--r-- | archival/libarchive/get_header_tar.c | 30 | ||||
-rw-r--r-- | archival/libarchive/unsafe_prefix.c | 36 | ||||
-rw-r--r-- | archival/unzip.c | 35 |
4 files changed, 63 insertions, 43 deletions
diff --git a/archival/libarchive/Kbuild.src b/archival/libarchive/Kbuild.src index 7e89e9e89..b7faaf77f 100644 --- a/archival/libarchive/Kbuild.src +++ b/archival/libarchive/Kbuild.src @@ -30,6 +30,7 @@ COMMON_FILES:= \ DPKG_FILES:= \ unpack_ar_archive.o \ filter_accept_list_reassign.o \ + unsafe_prefix.o \ get_header_ar.o \ get_header_tar.o \ get_header_tar_gz.o \ @@ -44,7 +45,7 @@ lib-$(CONFIG_DPKG_DEB) += $(DPKG_FILES) lib-$(CONFIG_AR) += get_header_ar.o unpack_ar_archive.o lib-$(CONFIG_CPIO) += get_header_cpio.o -lib-$(CONFIG_TAR) += get_header_tar.o +lib-$(CONFIG_TAR) += get_header_tar.o unsafe_prefix.o lib-$(CONFIG_FEATURE_TAR_TO_COMMAND) += data_extract_to_command.o lib-$(CONFIG_LZOP) += lzo1x_1.o lzo1x_1o.o lzo1x_d.o lib-$(CONFIG_LZOP_COMPR_HIGH) += lzo1x_9x.o @@ -53,7 +54,7 @@ lib-$(CONFIG_UNLZMA) += open_transformer.o decompress_unlzma. lib-$(CONFIG_UNXZ) += open_transformer.o decompress_unxz.o lib-$(CONFIG_GUNZIP) += open_transformer.o decompress_gunzip.o lib-$(CONFIG_UNCOMPRESS) += open_transformer.o decompress_uncompress.o -lib-$(CONFIG_UNZIP) += open_transformer.o decompress_gunzip.o +lib-$(CONFIG_UNZIP) += open_transformer.o decompress_gunzip.o unsafe_prefix.o lib-$(CONFIG_RPM2CPIO) += open_transformer.o decompress_gunzip.o get_header_cpio.o lib-$(CONFIG_RPM) += open_transformer.o decompress_gunzip.o get_header_cpio.o diff --git a/archival/libarchive/get_header_tar.c b/archival/libarchive/get_header_tar.c index ba43bb073..0c663fbd7 100644 --- a/archival/libarchive/get_header_tar.c +++ b/archival/libarchive/get_header_tar.c @@ -17,36 +17,6 @@ typedef uint32_t aliased_uint32_t FIX_ALIASING; typedef off_t aliased_off_t FIX_ALIASING; - -const char* FAST_FUNC strip_unsafe_prefix(const char *str) -{ - const char *cp = str; - while (1) { - char *cp2; - if (*cp == '/') { - cp++; - continue; - } - if (strncmp(cp, "/../"+1, 3) == 0) { - cp += 3; - continue; - } - cp2 = strstr(cp, "/../"); - if (!cp2) - break; - cp = cp2 + 4; - } - if (cp != str) { - static smallint warned = 0; - if (!warned) { - warned = 1; - bb_error_msg("removing leading '%.*s' from member names", - (int)(cp - str), str); - } - } - return cp; -} - /* NB: _DESTROYS_ str[len] character! */ static unsigned long long getOctal(char *str, int len) { diff --git a/archival/libarchive/unsafe_prefix.c b/archival/libarchive/unsafe_prefix.c new file mode 100644 index 000000000..826c673bf --- /dev/null +++ b/archival/libarchive/unsafe_prefix.c @@ -0,0 +1,36 @@ +/* vi: set sw=4 ts=4: */ +/* + * Licensed under GPLv2 or later, see file LICENSE in this source tree. + */ + +#include "libbb.h" +#include "bb_archive.h" + +const char* FAST_FUNC strip_unsafe_prefix(const char *str) +{ + const char *cp = str; + while (1) { + char *cp2; + if (*cp == '/') { + cp++; + continue; + } + if (strncmp(cp, "/../"+1, 3) == 0) { + cp += 3; + continue; + } + cp2 = strstr(cp, "/../"); + if (!cp2) + break; + cp = cp2 + 4; + } + if (cp != str) { + static smallint warned = 0; + if (!warned) { + warned = 1; + bb_error_msg("removing leading '%.*s' from member names", + (int)(cp - str), str); + } + } + return cp; +} diff --git a/archival/unzip.c b/archival/unzip.c index 38a07e212..eed225677 100644 --- a/archival/unzip.c +++ b/archival/unzip.c @@ -596,14 +596,18 @@ int unzip_main(int argc, char **argv) /* Skip extra header bytes */ unzip_skip(zip_header.formatted.extra_len); + /* Guard against "/abspath", "/../" and similar attacks */ + overlapping_strcpy(dst_fn, strip_unsafe_prefix(dst_fn)); + /* Filter zip entries */ if (find_list_entry(zreject, dst_fn) || (zaccept && !find_list_entry(zaccept, dst_fn)) ) { /* Skip entry */ i = 'n'; - } else { /* Extract entry */ - if (listing) { /* List entry */ + } else { + if (listing) { + /* List entry */ unsigned dostime = zip_header.formatted.modtime | (zip_header.formatted.moddate << 16); if (!verbose) { // " Length Date Time Name\n" @@ -639,9 +643,11 @@ int unzip_main(int argc, char **argv) total_size += zip_header.formatted.cmpsize; } i = 'n'; - } else if (dst_fd == STDOUT_FILENO) { /* Extracting to STDOUT */ + } else if (dst_fd == STDOUT_FILENO) { + /* Extracting to STDOUT */ i = -1; - } else if (last_char_is(dst_fn, '/')) { /* Extract directory */ + } else if (last_char_is(dst_fn, '/')) { + /* Extract directory */ if (stat(dst_fn, &stat_buf) == -1) { if (errno != ENOENT) { bb_perror_msg_and_die("can't stat '%s'", dst_fn); @@ -655,22 +661,27 @@ int unzip_main(int argc, char **argv) } } else { if (!S_ISDIR(stat_buf.st_mode)) { - bb_error_msg_and_die("'%s' exists but is not directory", dst_fn); + bb_error_msg_and_die("'%s' exists but is not a %s", + dst_fn, "directory"); } } i = 'n'; - } else { /* Extract file */ + } else { + /* Extract file */ check_file: - if (stat(dst_fn, &stat_buf) == -1) { /* File does not exist */ + if (stat(dst_fn, &stat_buf) == -1) { + /* File does not exist */ if (errno != ENOENT) { bb_perror_msg_and_die("can't stat '%s'", dst_fn); } i = 'y'; - } else { /* File already exists */ + } else { + /* File already exists */ if (overwrite == O_NEVER) { i = 'n'; - } else if (S_ISREG(stat_buf.st_mode)) { /* File is regular file */ + } else if (S_ISREG(stat_buf.st_mode)) { + /* File is regular file */ if (overwrite == O_ALWAYS) { i = 'y'; } else { @@ -678,8 +689,10 @@ int unzip_main(int argc, char **argv) my_fgets80(key_buf); i = key_buf[0]; } - } else { /* File is not regular file */ - bb_error_msg_and_die("'%s' exists but is not regular file", dst_fn); + } else { + /* File is not regular file */ + bb_error_msg_and_die("'%s' exists but is not a %s", + dst_fn, "regular file"); } } } |