mirrors/haproxy
1
0
Fork 0
mirror of https://git.haproxy.org/git/haproxy.git/ synced 2026-04-10 21:41:39 +02:00
Code Issues Projects Releases Wiki Activity

BUG/MEDIUM: jwe: fix NULL deref crash with empty CEK and non-dir alg

Browse Source 
In sample_conv_jwt_decrypt_secret(), when a JWE token has an empty
encrypted-key section but the algorithm is not "dir" (e.g. A128KW),
neither branch initializes decrypted_cek. The NULL pointer is then
passed to decrypt_ciphertext() which dereferences it:

  - For GCM encodings: aes_process() calls b_orig(NULL) -> SIGSEGV
  - For CBC encodings: b_data(NULL) at jwe.c:463 -> SIGSEGV

A single HTTP request with a crafted Authorization header crashes the
worker process. Trigger token (JOSE header {"alg":"A128KW","enc":"A128GCM"},
empty CEK section between the two dots):

  eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4R0NNIn0..AAAAAAAAAAAAAAAA.AA.AA

Reachable in any configuration using the jwt_decrypt_secret converter.
The other two decrypt converters (jwt_decrypt_jwk, jwt_decrypt_cert)
already have the check.

This must be backported as far as JWE support exists.
This commit is contained in:
Greg Kroah-Hartman 2026-04-07 09:48:09 +02:00 committed by William Lallemand
parent ed267f9bc5
commit 717e9aec5f
1 changed files with 4 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/jwe.c
View File

@ -718,6 +718,10 @@ static int sample_conv_jwt_decrypt_secret(const struct arg *args, struct sample
goto end;
chunk_memcpy(decrypted_cek, secret_smp.data.u.str.area, secret_smp.data.u.str.data);
} else {
/* Empty CEK with a non-"dir" algorithm: nothing we can use to
* derive a key. Bail out instead of passing NULL down. */
goto end;
}
/* Decode the encrypted content thanks to decrypted_cek secret */