Occasionally the MD5 hash for RSA-based digital signature
verification begins with zeros. A bug in how we convert the RSA
decoded plain text from a big number back to a hex string causes it
to write the number to the far left of the plain text buffer.
If the number is smaller than a hash, then zero-padding ends up on
the right when it should've been on the left.
Additional fix: BN_bn2bin() will write zero bytes if the bignum is 0.
So there is no point "error checking" the BN_bn2bin() call.
Thanks to Tom Judge for noticing these shenanigans.
Ref: https://github.com/openssl/openssl/issues/2101
Side note: BN_num_bytes() will also return 0 if the bignum is 0,
which is fine.
Freshclam may crash if using DatabaseCustomURL for a CVD and multiple
other files. The issue occurs because of a bad index in the "do not
prune" list.
Fixes: https://github.com/Cisco-Talos/clamav/issues/1364
If the 'hexsig' for an image fuzzy hash subsignature has invalid unicode
it may cause a crash. The problem is we fail to allocate an error
message in this instance, so when it tries to print that message it gets
a NULL dereference.
This is not a security issue.
Fixes: https://issues.oss-fuzz.com/issues/376331488
Store URLs found in HTML `<a>` and `<form>` tags during scan of HTML files
when recording scan metadata.
HTML URL recording will be ON by default, but is a part of the
generate-metadata-json feature.
The generate-metadata-json feature is OFF by default.
This introduces a new general scan option:
- libclamav: `CL_SCAN_GENERAL_STORE_HTML_URLS`.
- ClamD: `JsonStoreHTMLUrls`.
- ClamScan: `--json-store-html-urls`
Thank you Matt Jolly for the helpful comment on the pull request.
Add keys to the metadata.json file that informs the user that a scanned
ole2 file is encrypted. Information about the type of encryption is
provided when the information is available. This feature co-authored by
Micah Snyder.
There is presently no limit for the max-recursion scan option.
Selecting a max-recursion limit that is too high will cause confusing
errors. E.g.:
/home/aragusa/install.alz/bin/clamscan -d clamav.hdb . --max-recursion=9999999999
LibClamAV Error: fmap_fd: Attempted to get fd for NULL fmap
/home/aragusa/issue/clamav.hdb: Can't allocate memory ERROR
LibClamAV Error: fmap_fd: Attempted to get fd for NULL fmap
/home/aragusa/issue/test.sh: Can't allocate memory ERROR
This commit prevents setting the max-recursion limit higher than 100.
The log module used by clamd and freshclam may follow symlinks.
This is a potential security concern since the log may be owned by
the unprivileged service but may be opened by the service running as
root on startup.
For Windows, we'll define O_NOFOLLOW so the code works, though the issue
does not affect Windows.
Issue reported by Detlef.
The `find_length()` function in the PDF parser incorrectly assumes that
objects found are located in the main PDF file map, and fails to take
into account whether the objects were in fact found in extracted PDF
object streams. The resulting pointer is then invalid and may be an out
of bounds read.
This issue was found by OSS-Fuzz.
This fix checks if the object is from an object stream, and then
calculates the pointer based on the start of the object stream instead
of based on the start of the PDF.
I've also added extra checks to verify the calculated pointer and object
size are within the stream (or PDF file map). I'm not entirely sure this
is necessary, but better safe than sorry.
Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=69617
Somehow the changes from #692 did not come with a doc update. The cap at version 13 is given from #574. I did not try to build it with LLVM 14, so I don't know whether it truly doesn't compile or simply fails due to the CMake thing.
Clamscan and ClamD will throw an error if you use the
'--fail-if-cvd-older-than=DAYS' / 'FailIfCvdOlderThan' option and
try to load any plaintext signature files.
That is, it throws an error when encountering plain signature files like
`.ign2`, `.ldb`, `.hdb`, etc.
This feature should only verify CVD / CLD files.
The feature (and bug) was introduced in ClamAV 1.1.0, here:
e4fe6654c1
With this change, the `cl_cvdgetage` checks will skip any file that is
not a CVD or CLD.
Fixes: https://github.com/Cisco-Talos/clamav/issues/1174
Micah Snyder