Description
In the Linux kernel, the following vulnerability has been resolved: i2c: imx: fix locked bus on SMBus block-read of 0 (atomic) SMBus 3.1 6.5.7 allows a Block Read byte count of 0, but the atomic (polling) path rejects it as -EPROTO. Worse, it returns without a NACK+STOP: the next receive cycle has already started, so the target keeps holding SDA and the bus stays stuck until a power cycle for this i2c controller. Reading I2DR to obtain the count likewise arms the next byte on the count > I2C_SMBUS_BLOCK_MAX path, which also returned -EPROTO directly and left the bus held. Handle both: NACK the in-flight dummy byte (TXAK) and extend msgs->len so the existing last-byte handling emits STOP; the dummy byte is discarded. A count of 0 is a valid empty block read; a count above I2C_SMBUS_BLOCK_MAX is still reported as -EPROTO, but only after the bus has been released. The interrupt-driven path has the same flaw from a later commit and is fixed separately, as it carries a different Fixes: tag and stable range.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
8e8782c71595a5ad29e234ce6b3d2fce787fb07a to < 0f29df3c3d607a9dbc14aed0e45504ced4d2e7ecaffected8e8782c71595a5ad29e234ce6b3d2fce787fb07a to < 38d4947431b2410850409fda016b2ac9f640a4ddaffected8e8782c71595a5ad29e234ce6b3d2fce787fb07a to < e3e8b02d4773cfc5ad561d2e5505efde36c6927aaffected8e8782c71595a5ad29e234ce6b3d2fce787fb07a to < 016ef0f6ca4bc9bf0330ac41bd2ea349759643e3affected8e8782c71595a5ad29e234ce6b3d2fce787fb07a to < c882e8cc68fb993700dc21fd6e754001e6297934affected8e8782c71595a5ad29e234ce6b3d2fce787fb07a to < 6d2c973926d0612360693bc559be2ffde836151baffected8e8782c71595a5ad29e234ce6b3d2fce787fb07a to < 60ed00d46616a9232e42ea7a3e3c0273d7cf7543affected8e8782c71595a5ad29e234ce6b3d2fce787fb07a to < cb2fc37857693b55909fb77dc2c87cfbc1cdc476affected
Linux Linux
Default version status: affected
3.16affected0 to < 3.16unaffected5.10.266 to ≤ 5.10.*unaffected5.15.217 to ≤ 5.15.*unaffected6.1.184 to ≤ 6.1.*unaffected6.6.148 to ≤ 6.6.*unaffected6.12.101 to ≤ 6.12.*unaffected6.18.40 to ≤ 6.18.*unaffected7.1.5 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/0f29df3c3d607a9dbc14aed0e45504ced4d2e7ec ↗
- https://git.kernel.org/stable/c/38d4947431b2410850409fda016b2ac9f640a4dd ↗
- https://git.kernel.org/stable/c/e3e8b02d4773cfc5ad561d2e5505efde36c6927a ↗
- https://git.kernel.org/stable/c/016ef0f6ca4bc9bf0330ac41bd2ea349759643e3 ↗
- https://git.kernel.org/stable/c/c882e8cc68fb993700dc21fd6e754001e6297934 ↗
- https://git.kernel.org/stable/c/6d2c973926d0612360693bc559be2ffde836151b ↗
- https://git.kernel.org/stable/c/60ed00d46616a9232e42ea7a3e3c0273d7cf7543 ↗
- https://git.kernel.org/stable/c/cb2fc37857693b55909fb77dc2c87cfbc1cdc476 ↗