Commit a8064eea authored Mar 25, 2025 by Ekansh Gupta Committed by Liu Kai Mar 25, 2025

misc: fastrpc: Fix copy buffer page size

stable inclusion
from stable-v6.6.78
commit c0464bad0e85fcd5d47e4297d1e410097c979e55
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBPC3E
CVE: CVE-2025-21734

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=c0464bad0e85fcd5d47e4297d1e410097c979e55



--------------------------------

commit e966eae72762ecfdbdb82627e2cda48845b9dd66 upstream.

For non-registered buffer, fastrpc driver copies the buffer and
pass it to the remote subsystem. There is a problem with current
implementation of page size calculation which is not considering
the offset in the calculation. This might lead to passing of
improper and out-of-bounds page size which could result in
memory issue. Calculate page start and page end using the offset
adjusted address instead of absolute address.

Fixes: 02b45b47 ("misc: fastrpc: fix remote page size calculation")
Cc: stable@kernel.org
Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20250110134239.123603-4-srinivas.kandagatla@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Liu Kai <liukai284@huawei.com>

parent 0278be80

drivers/misc/fastrpc.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1015,8 +1015,8 @@ static int fastrpc_get_args(u32 kernel, struct fastrpc_invoke_ctx *ctx)
		(pkt_size - rlen);
		pages[i].addr = pages[i].addr & PAGE_MASK;

		pg_start = (args & PAGE_MASK) >> PAGE_SHIFT;
		pg_end = ((args + len - 1) & PAGE_MASK) >> PAGE_SHIFT;
		pg_start = (rpra[i].buf.pv & PAGE_MASK) >> PAGE_SHIFT;
		pg_end = ((rpra[i].buf.pv + len - 1) & PAGE_MASK) >> PAGE_SHIFT;
		pages[i].size = (pg_end - pg_start + 1) * PAGE_SIZE;
		args = args + mlen;
		rlen -= mlen;