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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 6/6] arm64/signal: Only read new data when parsing the ZA context
Date: Tue, 03 Jan 2023 20:25:20 +0000	[thread overview]
Message-ID: <20221212-arm64-signal-cleanup-v2-6-14a8f3e088b7@kernel.org> (raw)
In-Reply-To: <20221212-arm64-signal-cleanup-v2-0-14a8f3e088b7@kernel.org>

When we parse the ZA 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 | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 26192ab56de4..bed27d4f8ce9 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -401,17 +401,18 @@ static int preserve_za_context(struct za_context __user *ctx)
 
 static int restore_za_context(struct user_ctxs *user)
 {
-	int err;
+	int err = 0;
 	unsigned int vq;
-	struct za_context za;
+	u16 user_vl;
 
 	if (user->za_size < sizeof(*user->za))
 		return -EINVAL;
 
-	if (__copy_from_user(&za, user->za, sizeof(za)))
-		return -EFAULT;
+	__get_user_error(user_vl, &(user->za->vl), err);
+	if (err)
+		return err;
 
-	if (za.vl != task_get_sme_vl(current))
+	if (user_vl != task_get_sme_vl(current))
 		return -EINVAL;
 
 	if (user->za_size == sizeof(*user->za)) {
@@ -419,7 +420,7 @@ static int restore_za_context(struct user_ctxs *user)
 		return 0;
 	}
 
-	vq = sve_vq_from_vl(za.vl);
+	vq = sve_vq_from_vl(user_vl);
 
 	if (user->za_size < ZA_SIG_CONTEXT_SIZE(vq))
 		return -EINVAL;

-- 
2.30.2

WARNING: multiple messages have this Message-ID (diff)
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 6/6] arm64/signal: Only read new data when parsing the ZA context
Date: Tue, 03 Jan 2023 20:25:20 +0000	[thread overview]
Message-ID: <20221212-arm64-signal-cleanup-v2-6-14a8f3e088b7@kernel.org> (raw)
In-Reply-To: <20221212-arm64-signal-cleanup-v2-0-14a8f3e088b7@kernel.org>

When we parse the ZA 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 | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 26192ab56de4..bed27d4f8ce9 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -401,17 +401,18 @@ static int preserve_za_context(struct za_context __user *ctx)
 
 static int restore_za_context(struct user_ctxs *user)
 {
-	int err;
+	int err = 0;
 	unsigned int vq;
-	struct za_context za;
+	u16 user_vl;
 
 	if (user->za_size < sizeof(*user->za))
 		return -EINVAL;
 
-	if (__copy_from_user(&za, user->za, sizeof(za)))
-		return -EFAULT;
+	__get_user_error(user_vl, &(user->za->vl), err);
+	if (err)
+		return err;
 
-	if (za.vl != task_get_sme_vl(current))
+	if (user_vl != task_get_sme_vl(current))
 		return -EINVAL;
 
 	if (user->za_size == sizeof(*user->za)) {
@@ -419,7 +420,7 @@ static int restore_za_context(struct user_ctxs *user)
 		return 0;
 	}
 
-	vq = sve_vq_from_vl(za.vl);
+	vq = sve_vq_from_vl(user_vl);
 
 	if (user->za_size < ZA_SIG_CONTEXT_SIZE(vq))
 		return -EINVAL;

-- 
2.30.2

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2023-01-03 20:26 UTC|newest]

Thread overview: 22+ 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 ` 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   ` 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   ` 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   ` 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
2023-01-03 20:25 ` [PATCH v2 5/6] arm64/signal: Only read new data when parsing the SVE context Mark Brown
2023-01-03 20:25   ` 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 12:51   ` Catalin Marinas
2023-01-31 13:14   ` Mark Brown
2023-01-31 13:14     ` Mark Brown
2023-01-31 15:38   ` Will Deacon
2023-01-31 15:38     ` Will Deacon
2023-02-01 11:52     ` Catalin Marinas
2023-02-01 11:52       ` Catalin Marinas

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