From: Ekansh Gupta <quic_ekangupt@quicinc.com> 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=... -------------------------------- 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: 02b45b47fbe8 ("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... Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Liu Kai <liukai284@huawei.com> --- drivers/misc/fastrpc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index 4df0d7a0cd11..6c77d56847d8 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -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; -- 2.34.1