From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Mark Brown <broonie@kernel.org>
Subject: [PATCH v2 5/6] arm64/signal: Only read new data when parsing the SVE context
Date: Tue, 03 Jan 2023 20:25:19 +0000 [thread overview]
Message-ID: <20221212-arm64-signal-cleanup-v2-5-14a8f3e088b7@kernel.org> (raw)
In-Reply-To: <20221212-arm64-signal-cleanup-v2-0-14a8f3e088b7@kernel.org>
When we parse the SVE 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 <broonie@kernel.org>
---
arch/arm64/kernel/signal.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 82a89b0852ee..26192ab56de4 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -265,18 +265,20 @@ static int preserve_sve_context(struct sve_context __user *ctx)
static int restore_sve_fpsimd_context(struct user_ctxs *user)
{
- int err;
+ int err = 0;
unsigned int vl, vq;
struct user_fpsimd_state fpsimd;
- struct sve_context sve;
+ u16 user_vl, flags;
if (user->sve_size < sizeof(*user->sve))
return -EINVAL;
- if (__copy_from_user(&sve, user->sve, sizeof(sve)))
- return -EFAULT;
+ __get_user_error(user_vl, &(user->sve->vl), err);
+ __get_user_error(flags, &(user->sve->flags), err);
+ if (err)
+ return err;
- if (sve.flags & SVE_SIG_FLAG_SM) {
+ if (flags & SVE_SIG_FLAG_SM) {
if (!system_supports_sme())
return -EINVAL;
@@ -288,7 +290,7 @@ static int restore_sve_fpsimd_context(struct user_ctxs *user)
vl = task_get_sve_vl(current);
}
- if (sve.vl != vl)
+ if (user_vl != vl)
return -EINVAL;
if (user->sve_size == sizeof(*user->sve)) {
@@ -298,7 +300,7 @@ static int restore_sve_fpsimd_context(struct user_ctxs *user)
goto fpsimd_only;
}
- vq = sve_vq_from_vl(sve.vl);
+ vq = sve_vq_from_vl(vl);
if (user->sve_size < SVE_SIG_CONTEXT_SIZE(vq))
return -EINVAL;
@@ -326,7 +328,7 @@ static int restore_sve_fpsimd_context(struct user_ctxs *user)
if (err)
return -EFAULT;
- if (sve.flags & SVE_SIG_FLAG_SM)
+ if (flags & SVE_SIG_FLAG_SM)
current->thread.svcr |= SVCR_SM_MASK;
else
set_thread_flag(TIF_SVE);
--
2.30.2
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next prev parent reply other threads:[~2023-01-03 20:29 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-03 20:25 [PATCH v2 0/6] arm64/signal: Signal handling cleanups Mark Brown
2023-01-03 20:25 ` [PATCH v2 1/6] arm64/signal: Don't redundantly verify FPSIMD magic Mark Brown
2023-01-03 20:25 ` [PATCH v2 2/6] arm64/signal: Remove redundant size validation from parse_user_sigframe() Mark Brown
2023-01-03 20:25 ` [PATCH v2 3/6] arm64/signal: Make interface for restore_fpsimd_context() consistent Mark Brown
2023-01-03 20:25 ` [PATCH v2 4/6] arm64/signal: Avoid rereading context frame sizes Mark Brown
2023-01-03 20:25 ` Mark Brown [this message]
2023-01-03 20:25 ` [PATCH v2 6/6] arm64/signal: Only read new data when parsing the ZA context Mark Brown
2023-01-31 12:51 ` [PATCH v2 0/6] arm64/signal: Signal handling cleanups Catalin Marinas
2023-01-31 13:14 ` Mark Brown
2023-01-31 15:38 ` Will Deacon
2023-02-01 11:52 ` Catalin Marinas
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