In the Linux kernel, the following vulnerability has been resolved:
keys: make keyring key-chunk byte order agree with keyring_diff_objects()
keyring_get_key_chunk() loads description bytes into the index chunk low address first, while keyring_diff_objects() numbers the first differing bit from the low end and folds the absolute byte index into the level without removing the inline-prefix offset the level already carries. The two disagree on byte order and bit position, so the array can be told two keys first differ at a bit that does not differ in the chunk the walker uses, letting crafted descriptions collide into one node.
Load the chunk in the order keyring_diff_objects() assumes and drop the inline-prefix length when folding the byte index into the level. This only changes the in-memory ordering used to place keys within a keyring; add, search and read of non-colliding keys are unaffected.
References
- https://git.kernel.org/stable/c/3d9f16c0b643ceac305526b2e2fe25c2c6166926
- https://git.kernel.org/stable/c/58565eef0f8d861aae92abfb7658458d661cee17
- https://git.kernel.org/stable/c/7269df3e7fcfa308e6a456305162f7788747bdbd
- https://git.kernel.org/stable/c/7e5397a3fed0dee7779bd084bec3c0584db3c930
- https://git.kernel.org/stable/c/bd0f976ef89dce6db458bf75bc2cf51127becc41