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*); |