CVE-2022-49452

In the Linux kernel, the following vulnerability has been resolved:

dpaa2-eth: retrieve the virtual address before dma_unmap

The TSO header was DMA unmapped before the virtual address was retrieved and then used to free the buffer. This meant that we were actually removing the DMA map and then trying to search for it to help in retrieving the virtual address. This lead to a invalid virtual address being used in the kfree call.

Fix this by calling dpaa2_iova_to_virt() prior to the dma_unmap call.

[ 487.231819] Unable to handle kernel paging request at virtual address fffffd9807000008

(…)

[ 487.354061] Hardware name: SolidRun LX2160A Honeycomb (DT) [ 487.359535] pstate: a0400005 (NzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=–) [ 487.366485] pc : kfree+0xac/0x304 [ 487.369799] lr : kfree+0x204/0x304 [ 487.373191] sp : ffff80000c4eb120 [ 487.376493] x29: ffff80000c4eb120 x28: ffff662240c46400 x27: 0000000000000001 [ 487.383621] x26: 0000000000000001 x25: ffff662246da0cc0 x24: ffff66224af78000 [ 487.390748] x23: ffffad184f4ce008 x22: ffffad1850185000 x21: ffffad1838d13cec [ 487.397874] x20: ffff6601c0000000 x19: fffffd9807000000 x18: 0000000000000000 [ 487.405000] x17: ffffb910cdc49000 x16: ffffad184d7d9080 x15: 0000000000004000 [ 487.412126] x14: 0000000000000008 x13: 000000000000ffff x12: 0000000000000000 [ 487.419252] x11: 0000000000000004 x10: 0000000000000001 x9 : ffffad184d7d927c [ 487.426379] x8 : 0000000000000000 x7 : 0000000ffffffd1d x6 : ffff662240a94900 [ 487.433505] x5 : 0000000000000003 x4 : 0000000000000009 x3 : ffffad184f4ce008 [ 487.440632] x2 : ffff662243eec000 x1 : 0000000100000100 x0 : fffffc0000000000 [ 487.447758] Call trace: [ 487.450194] kfree+0xac/0x304 [ 487.453151] dpaa2_eth_free_tx_fd.isra.0+0x33c/0x3e0 [fsl_dpaa2_eth] [ 487.459507] dpaa2_eth_tx_conf+0x100/0x2e0 [fsl_dpaa2_eth] [ 487.464989] dpaa2_eth_poll+0xdc/0x380 [fsl_dpaa2_eth]

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/06d129946a71f3159b3b40ee95549183edf2c79d
• https://git.kernel.org/stable/c/ba5fe3dd4833bbc03609c5c0c2dd2cea5fa5addf