Re: [PATCH v2 61/63] powerpc: Split memset() to avoid multi-field overflow
From: Christophe Leroy <hidden>
Date: 2021-08-18 06:42:36
Also in:
dri-devel, linux-hardening, linux-kbuild, linux-staging, linux-wireless, linuxppc-dev, lkml, netdev
Le 18/08/2021 à 08:05, Kees Cook a écrit :
quoted hunk ↗ jump to hunk
In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields. Instead of writing across a field boundary with memset(), move the call to just the array, and an explicit zeroing of the prior field. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Qinglang Miao <redacted> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> Cc: Hulk Robot <redacted> Cc: Wang Wensheng <redacted> Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Kees Cook <redacted> Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/lkml/87czqsnmw9.fsf@mpe.ellerman.id.au (local) --- drivers/macintosh/smu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)diff --git a/drivers/macintosh/smu.c b/drivers/macintosh/smu.c index 94fb63a7b357..59ce431da7ef 100644 --- a/drivers/macintosh/smu.c +++ b/drivers/macintosh/smu.c@@ -848,7 +848,8 @@ int smu_queue_i2c(struct smu_i2c_cmd *cmd) cmd->read = cmd->info.devaddr & 0x01; switch(cmd->info.type) { case SMU_I2C_TRANSFER_SIMPLE: - memset(&cmd->info.sublen, 0, 4); + cmd->info.sublen = 0; + memset(&cmd->info.subaddr, 0, 3);
subaddr[] is a table, should the & be avoided ? And while at it, why not use sizeof(subaddr) instead of 3 ?
break; case SMU_I2C_TRANSFER_COMBINED: cmd->info.devaddr &= 0xfe;