block: don't overwrite bip_vcnt in bio_integrity_copy_user()
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.8epss 0.2%
exploitation probability
0.2%top 94% of all CVEs
observed exploitation
nono source reports it
In the Linux kernel, the following vulnerability has been resolved:
block: don't overwrite bip_vcnt in bio_integrity_copy_user()
bio_integrity_add_page() already sets bip_vcnt to 1 for the bounce
segment. Overwriting it with nr_vecs breaks bip_vcnt <= bip_max_vcnt
on WRITE (bip_max_vcnt is 1), so the gap-merge checks in block/blk.h
read past the bip_vec[] flex array. On READ the read is in bounds
but lands on a saved user bvec instead of the bounce.
The line was added for split propagation, but bio_integrity_clone()
doesn't copy bip_vcnt and BIP_CLONE_FLAGS excludes BIP_COPY_USER.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected products
Linux · Linux