| 0,0 → 1,105 |
|---|
| Author: Raphael Geissert <geissert@debian.org> |
| Bug-Debian: https://bugs.debian.org/731860 |
| Description: Avoid directory traversal when extracting archives |
| by skipping over leading slashes and any prefix containing ".." components. |
| Forwarded: yes |
| |
| --- a/lib/decode.c |
| +++ b/lib/decode.c |
| @@ -21,13 +21,42 @@ |
| # include <string.h> |
| #endif |
| |
| +char * |
| +safer_name_suffix (char const *file_name) |
| +{ |
| + char const *p, *t; |
| + p = t = file_name; |
| + while (*p == '/') t = ++p; |
| + while (*p) |
| + { |
| + while (p[0] == '.' && p[0] == p[1] && p[2] == '/') |
| + { |
| + p += 3; |
| + t = p; |
| + } |
| + /* advance pointer past the next slash */ |
| + while (*p && (p++)[0] != '/'); |
| + } |
| + |
| + if (!*t) |
| + { |
| + t = "."; |
| + } |
| + |
| + if (t != file_name) |
| + { |
| + /* TODO: warn somehow that the path was modified */ |
| + } |
| + return (char*)t; |
| +} |
| + |
| |
| /* determine full path name */ |
| char * |
| th_get_pathname(TAR *t) |
| { |
| if (t->th_buf.gnu_longname) |
| - return t->th_buf.gnu_longname; |
| + return safer_name_suffix(t->th_buf.gnu_longname); |
| |
| size_t pathlen = |
| strlen(t->th_buf.prefix) + strlen(t->th_buf.name) + 2; |
| @@ -43,12 +72,12 @@ th_get_pathname(TAR *t) |
| |
| if (t->th_buf.prefix[0] == '\0') |
| { |
| - snprintf(t->th_pathname, pathlen, "%.100s", t->th_buf.name); |
| + snprintf(t->th_pathname, pathlen, "%.100s", safer_name_suffix(t->th_buf.name)); |
| } |
| else |
| { |
| snprintf(t->th_pathname, pathlen, "%.155s/%.100s", |
| - t->th_buf.prefix, t->th_buf.name); |
| + t->th_buf.prefix, safer_name_suffix(t->th_buf.name)); |
| } |
| |
| /* will be deallocated in tar_close() */ |
| --- a/lib/extract.c |
| +++ b/lib/extract.c |
| @@ -298,14 +298,14 @@ tar_extract_hardlink(TAR * t, char *real |
| if (mkdirhier(dirname(filename)) == -1) |
| return -1; |
| libtar_hashptr_reset(&hp); |
| - if (libtar_hash_getkey(t->h, &hp, th_get_linkname(t), |
| + if (libtar_hash_getkey(t->h, &hp, safer_name_suffix(th_get_linkname(t)), |
| (libtar_matchfunc_t)libtar_str_match) != 0) |
| { |
| lnp = (char *)libtar_hashptr_data(&hp); |
| linktgt = &lnp[strlen(lnp) + 1]; |
| } |
| else |
| - linktgt = th_get_linkname(t); |
| + linktgt = safer_name_suffix(th_get_linkname(t)); |
| |
| #ifdef DEBUG |
| printf(" ==> extracting: %s (link to %s)\n", filename, linktgt); |
| @@ -343,9 +343,9 @@ tar_extract_symlink(TAR *t, char *realna |
| |
| #ifdef DEBUG |
| printf(" ==> extracting: %s (symlink to %s)\n", |
| - filename, th_get_linkname(t)); |
| + filename, safer_name_suffix(th_get_linkname(t))); |
| #endif |
| - if (symlink(th_get_linkname(t), filename) == -1) |
| + if (symlink(safer_name_suffix(th_get_linkname(t)), filename) == -1) |
| { |
| #ifdef DEBUG |
| perror("symlink()"); |
| --- a/lib/internal.h |
| +++ b/lib/internal.h |
| @@ -21,3 +21,4 @@ |
| #define TLS_THREAD |
| #endif |
| |
| +char* safer_name_suffix(char const*); |