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| author | Daniel Axtens <dja@axtens.net> | 2018-12-04 14:29:42 +1100 |
|---|---|---|
| committer | Daniel Axtens <dja@axtens.net> | 2018-12-11 13:58:11 +1100 |
| commit | 15bf44fd2c1ad0e3fd87048b3fcc90c4dcff1175 (patch) | |
| tree | ff6e8214fcfb31ee79012706607a52feeec9b81e | |
| parent | bfcfe6f04ed20db2504db8a254d1f40a1d84eb28 (diff) | |
| download | libarchive-15bf44fd2c1ad0e3fd87048b3fcc90c4dcff1175.tar.gz | |
Skip 0-length ACL fields
Currently, it is possible to create an archive that crashes bsdtar
with a malformed ACL:
Program received signal SIGSEGV, Segmentation fault.
archive_acl_from_text_l (acl=<optimised out>, text=0x7e2e92 "", want_type=<optimised out>, sc=<optimised out>) at libarchive/archive_acl.c:1726
1726 switch (*s) {
(gdb) p n
$1 = 1
(gdb) p field[n]
$2 = {start = 0x0, end = 0x0}
Stop this by checking that the length is not zero before beginning
the switch statement.
I am pretty sure this is the bug mentioned in the qsym paper [1],
and I was able to replicate it with a qsym + AFL + afl-rb setup.
[1] https://www.usenix.org/conference/usenixsecurity18/presentation/yun
| -rw-r--r-- | libarchive/archive_acl.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/libarchive/archive_acl.c b/libarchive/archive_acl.c index 512beee1..7beeee86 100644 --- a/libarchive/archive_acl.c +++ b/libarchive/archive_acl.c @@ -1723,6 +1723,11 @@ archive_acl_from_text_l(struct archive_acl *acl, const char *text, st = field[n].start + 1; len = field[n].end - field[n].start; + if (len == 0) { + ret = ARCHIVE_WARN; + continue; + } + switch (*s) { case 'u': if (len == 1 || (len == 4 |