From ad678be4238720384fa9e21b9b08b5540ac7ca5d Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Tue, 31 Jan 2023 22:20:45 +0000 Subject: [PATCH] arm64/signal: Only read new data when parsing the ZT context When we parse the ZT signal context we read the entire context from userspace, including the generic signal context header which was already read by parse_user_sigframe() and padding bytes that we ignore. Avoid the possibility of relying on the second read of the data read twice by only reading the data which we are actually going to use. Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20221212-arm64-signal-cleanup-v3-7-4545c94b20ff@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kernel/signal.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 7810d09..d7b5ed8 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -521,7 +521,7 @@ static int preserve_zt_context(struct zt_context __user *ctx) static int restore_zt_context(struct user_ctxs *user) { int err; - struct zt_context zt; + u16 nregs; /* ZA must be restored first for this check to be valid */ if (!thread_za_enabled(¤t->thread)) @@ -530,10 +530,10 @@ static int restore_zt_context(struct user_ctxs *user) if (user->zt_size != ZT_SIG_CONTEXT_SIZE(1)) return -EINVAL; - if (__copy_from_user(&zt, user->zt, sizeof(zt))) + if (__copy_from_user(&nregs, &(user->zt->nregs), sizeof(nregs))) return -EFAULT; - if (zt.nregs != 1) + if (nregs != 1) return -EINVAL; /* -- 2.7.4