Description

In the Linux kernel, the following vulnerability has been resolved: spi: tegra210-quad: Protect curr_xfer check in IRQ handler Now that all other accesses to curr_xfer are done under the lock, protect the curr_xfer NULL check in tegra_qspi_isr_thread() with the spinlock. Without this protection, the following race can occur: CPU0 (ISR thread) CPU1 (timeout path) ---------------- ------------------- if (!tqspi->curr_xfer) // sees non-NULL spin_lock() tqspi->curr_xfer = NULL spin_unlock() handle_*_xfer() spin_lock() t = tqspi->curr_xfer // NULL! ... t->len ... // NULL dereference! With this patch, all curr_xfer accesses are now properly synchronized. Although all accesses to curr_xfer are done under the lock, in tegra_qspi_isr_thread() it checks for NULL, releases the lock and reacquires it later in handle_cpu_based_xfer()/handle_dma_based_xfer(). There is a potential for an update in between, which could cause a NULL pointer dereference. To handle this, add a NULL check inside the handlers after acquiring the lock. This ensures that if the timeout path has already cleared curr_xfer, the handler will safely return without dereferencing the NULL pointer.

Weaknesses 2

Affected Products 14

References 3

• git.kernel.org https://git.kernel.org/stable/c/2ac3a105e51496147c0e44e49466eecfcc532d57
  Patch
• git.kernel.org https://git.kernel.org/stable/c/84e926c1c272a35ddb9b86842d32fa833a60dfc7
• git.kernel.org https://git.kernel.org/stable/c/edf9088b6e1d6d88982db7eb5e736a0e4fbcc09e
  Patch

Remediation

• git.kernel.org https://git.kernel.org/stable/c/2ac3a105e51496147c0e44e49466eecfcc532d57
  Patch
• git.kernel.org https://git.kernel.org/stable/c/edf9088b6e1d6d88982db7eb5e736a0e4fbcc09e
  Patch