From f3ac48aa3a58b0d0b1104416a652dc7da9c03b4a Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Tue, 31 Jan 2023 22:20:43 +0000 Subject: arm64/signal: Only read new data when parsing the SVE context 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 Link: https://lore.kernel.org/r/20221212-arm64-signal-cleanup-v3-5-4545c94b20ff@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kernel/signal.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) (limited to 'arch') diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 567e8e5b6998..27a1fa37f926 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -271,18 +271,20 @@ 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; @@ -294,7 +296,7 @@ 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)) { @@ -304,7 +306,7 @@ 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; @@ -332,7 +334,7 @@ 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); -- cgit v1.2.3