CVE-2026-43492
In the Linux kernel, the following vulnerability has been resolved: lib/crypto: mpi: Fix integer underflow in mpi_read_raw_from_sgl() Yiming reports an integer underflow in mpi_read_raw_from_sgl() when subtracting "lzeros" from the unsigned "nbytes". For this to happen, the scatterlist "sgl" needs to occupy more bytes than the "nbytes" parameter and the first "nbytes + 1" bytes of the scatterlist must be zero. Under these conditions, the while loop iterating over the scatterlist will count more zeroes than "nbytes", subtract the number of zeroes from "nbytes" and cause the underflow. When commit 2d4d1eea540b ("lib/mpi: Add mpi sgl helpers") originally introduced the bug, it couldn't be triggered because all callers of mpi_read_raw_from_sgl() passed a scatterlist whose length was equal to "nbytes". However since commit 63ba4d67594a ("KEYS: asymmetric: Use new crypto interface without scatterlists"), the underflow can now actually be triggered. When invoking a KEYCTL_PKEY_ENCRYPT system call with a larger "out_len" than "in_len" and filling the "in" buffer with zeroes, crypto_akcipher_sync_prep() will create an all-zero scatterlist used for both the "src" and "dst" member of struct a
Faiblesse
In the Linux kernel, the following vulnerability has been resolved: lib/crypto: mpi: Fix integer underflow in mpi_read_raw_from_sgl() Yiming reports an integer underflow in mpi_read_raw_from_sgl() when subtracting "lzeros" from the unsigned "nbytes". For this to happen, the scatterlist "sgl" needs to occupy more bytes than the "nbytes" parameter and the first "nbytes + 1" bytes of the scatterlist must be zero. Under these conditions, the while loop iterating over the scatterlist will count more zeroes than "nbytes", subtract the number of zeroes from "nbytes" and cause the underflow. When commit 2d4d1eea540b ("lib/mpi: Add mpi sgl helpers") originally introduced the bug, it couldn't be triggered because all callers of mpi_read_raw_from_sgl() passed a scatterlist whose length was equal to "nbytes". However since commit 63ba4d67594a ("KEYS: asymmetric: Use new crypto interface without scatterlists"), the underflow can now actually be triggered. When invoking a KEYCTL_PKEY_ENCRYPT system call with a larger "out_len" than "in_len" and filling the "in" buffer with zeroes, crypto_akcipher_sync_prep() will create an all-zero scatterlist used for both the "src" and "dst" member of struct a
Produits concernés
- linux linux_kernel
Références
- https://git.kernel.org/stable/c/1abd50fc3cfa16fc2074a3c8c2729c50fd9d7043
- https://git.kernel.org/stable/c/26d3a97ad46c7a9226ec04d4bf35bd4998a97d16
- https://git.kernel.org/stable/c/2aa77a18dc7f2670497fe3ee5acbeda0b57659e5
- https://git.kernel.org/stable/c/30e513e755bb381afce6fb57cdc8694136193f22
- https://git.kernel.org/stable/c/6d63615c796c085b4984e3031b9fa77fffb47360
- https://git.kernel.org/stable/c/8637dfb4c1d8a7026ef681f2477c6de8b71c4003
Trouvez la faille avant un attaquant.
Connectez-vous avec GitHub et lancez votre premier audit en moins d'une minute. L'offre gratuite ne nécessite aucune carte bancaire.