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| author | Timo Teräs <timo.teras@iki.fi> | 2021-04-11 15:21:42 +0300 |
|---|---|---|
| committer | Timo Teräs <timo.teras@iki.fi> | 2021-04-12 15:30:14 +0300 |
| commit | f7143c1766ae59489ac922e890ffe6d4a61c3b2d (patch) | |
| tree | bbeed012d9bc90374b10a79f26acfbb56c33a750 | |
| parent | 4bcd792194c23fd73912a567101af5fda6e860da (diff) | |
| download | apk-tools-f7143c1766ae59489ac922e890ffe6d4a61c3b2d.tar.gz apk-tools-f7143c1766ae59489ac922e890ffe6d4a61c3b2d.tar.bz2 apk-tools-f7143c1766ae59489ac922e890ffe6d4a61c3b2d.tar.xz apk-tools-f7143c1766ae59489ac922e890ffe6d4a61c3b2d.zip | |
io_archive: add bounds limit for uname and gname tar header fields
Modify apk_resolve_[ug]id to take the user/groupname as a blob, so
proper length checking is done and honored.
==31584== Conditional jump or move depends on uninitialised value(s)
==31584== at 0x5C8CA5: strlen (strlen.c:17)
==31584== by 0x432575: APK_BLOB_STR (apk_blob.h:79)
==31584== by 0x4350EB: apk_resolve_uid (io.c:1112)
==31584== by 0x43696C: apk_tar_parse (io_archive.c:152)
==31584== by 0x4271BC: apk_pkg_read (package.c:929)
==31584== by 0x402D75: add_main (app_add.c:163)
==31584== by 0x40D5FF: main (apk-static.c:516)
Fixes a potential crash (DoS) on a crafted TAR file. CVE-2021-30139.
Reported-by: Sören Tempel <soeren+git@soeren-tempel.net>
Reviewed-by: Ariadne Conill <ariadne@dereferenced.org>
| -rw-r--r-- | src/apk_io.h | 4 | ||||
| -rw-r--r-- | src/io.c | 12 | ||||
| -rw-r--r-- | src/io_archive.c | 5 |
3 files changed, 11 insertions, 10 deletions
diff --git a/src/apk_io.h b/src/apk_io.h index fcdbebc..eafb12f 100644 --- a/src/apk_io.h +++ b/src/apk_io.h @@ -180,7 +180,7 @@ const char *apk_url_local_file(const char *url); void apk_id_cache_init(struct apk_id_cache *idc, int root_fd); void apk_id_cache_free(struct apk_id_cache *idc); void apk_id_cache_reset(struct apk_id_cache *idc); -uid_t apk_resolve_uid(struct apk_id_cache *idc, const char *username, uid_t default_uid); -uid_t apk_resolve_gid(struct apk_id_cache *idc, const char *groupname, uid_t default_gid); +uid_t apk_resolve_uid(struct apk_id_cache *idc, apk_blob_t username, uid_t default_uid); +uid_t apk_resolve_gid(struct apk_id_cache *idc, apk_blob_t groupname, uid_t default_gid); #endif @@ -1114,7 +1114,7 @@ static FILE *fopenat(int dirfd, const char *pathname) return f; } -uid_t apk_resolve_uid(struct apk_id_cache *idc, const char *username, uid_t default_uid) +uid_t apk_resolve_uid(struct apk_id_cache *idc, apk_blob_t username, uid_t default_uid) { #ifdef HAVE_FGETPWENT_R char buf[1024]; @@ -1124,7 +1124,7 @@ uid_t apk_resolve_uid(struct apk_id_cache *idc, const char *username, uid_t defa struct passwd *pwd; FILE *in; - ci = resolve_cache_item(&idc->uid_cache, APK_BLOB_STR(username)); + ci = resolve_cache_item(&idc->uid_cache, username); if (ci == NULL) return default_uid; if (ci->genid != idc->genid) { @@ -1141,7 +1141,7 @@ uid_t apk_resolve_uid(struct apk_id_cache *idc, const char *username, uid_t defa #endif if (pwd == NULL) break; - if (strcmp(pwd->pw_name, username) == 0) { + if (apk_blob_compare(APK_BLOB_STR(pwd->pw_name), username) == 0) { ci->uid = pwd->pw_uid; break; } @@ -1156,7 +1156,7 @@ uid_t apk_resolve_uid(struct apk_id_cache *idc, const char *username, uid_t defa return default_uid; } -uid_t apk_resolve_gid(struct apk_id_cache *idc, const char *groupname, uid_t default_gid) +uid_t apk_resolve_gid(struct apk_id_cache *idc, apk_blob_t groupname, uid_t default_gid) { #ifdef HAVE_FGETGRENT_R char buf[1024]; @@ -1166,7 +1166,7 @@ uid_t apk_resolve_gid(struct apk_id_cache *idc, const char *groupname, uid_t def struct group *grp; FILE *in; - ci = resolve_cache_item(&idc->gid_cache, APK_BLOB_STR(groupname)); + ci = resolve_cache_item(&idc->gid_cache, groupname); if (ci == NULL) return default_gid; if (ci->genid != idc->genid) { @@ -1183,7 +1183,7 @@ uid_t apk_resolve_gid(struct apk_id_cache *idc, const char *groupname, uid_t def #endif if (grp == NULL) break; - if (strcmp(grp->gr_name, groupname) == 0) { + if (apk_blob_compare(APK_BLOB_STR(grp->gr_name), groupname) == 0) { ci->gid = grp->gr_gid; break; } diff --git a/src/io_archive.c b/src/io_archive.c index de4741e..303fb93 100644 --- a/src/io_archive.c +++ b/src/io_archive.c @@ -49,6 +49,7 @@ struct tar_header { char padding[12]; /* 500-511 */ }; +#define TAR_BLOB(s) APK_BLOB_PTR_LEN(s, strnlen(s, sizeof(s))) #define GET_OCTAL(s) get_octal(s, sizeof(s)) #define PUT_OCTAL(s,v) put_octal(s, sizeof(s), v) @@ -149,8 +150,8 @@ int apk_tar_parse(struct apk_istream *is, apk_archive_entry_parser parser, entry = (struct apk_file_info){ .size = GET_OCTAL(buf.size), - .uid = apk_resolve_uid(idc, buf.uname, GET_OCTAL(buf.uid)), - .gid = apk_resolve_gid(idc, buf.gname, GET_OCTAL(buf.gid)), + .uid = apk_resolve_uid(idc, TAR_BLOB(buf.uname), GET_OCTAL(buf.uid)), + .gid = apk_resolve_gid(idc, TAR_BLOB(buf.gname), GET_OCTAL(buf.gid)), .mode = GET_OCTAL(buf.mode) & 07777, .mtime = GET_OCTAL(buf.mtime), .name = entry.name, |