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[Linux-stable-mirror] [PATCH 4.4] net/mac80211/debugfs.c: prevent build failure with CONFIG_UBSAN=y

by Daniel Wagner

From: Andrey Ryabinin <aryabinin(a)virtuozzo.com> commit 68920c973254c5b71a684645c5f6f82d6732c5d6 upstream. With upcoming CONFIG_UBSAN the following BUILD_BUG_ON in net/mac80211/debugfs.c starts to trigger: BUILD_BUG_ON(hw_flag_names[NUM_IEEE80211_HW_FLAGS] != (void *)0x1); It seems, that compiler instrumentation causes some code deoptimizations. Because of that GCC is not being able to resolve condition in BUILD_BUG_ON() at compile time. We could make size of hw_flag_names array unspecified and replace the condition in BUILD_BUG_ON() with following: ARRAY_SIZE(hw_flag_names) != NUM_IEEE80211_HW_FLAGS That will have the same effect as before (adding new flag without updating array will trigger build failure) except it doesn't fail with CONFIG_UBSAN. As a bonus this patch slightly decreases size of hw_flag_names array. Signed-off-by: Andrey Ryabinin <aryabinin(a)virtuozzo.com> Cc: Johannes Berg <johannes(a)sipsolutions.net> Cc: "David S. Miller" <davem(a)davemloft.net> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds(a)linux-foundation.org> [Daniel: backport to 4.4.] Signed-off-by: Daniel Wagner <daniel.wagner(a)siemens.com> --- Hi, The only stable tree which is missing this fix is 4.4. 4.1 doesn't have 30686bf7f5b3 ("mac80211: convert HW flags to unsigned long bitmap") which makes gcc unhappy with allmodconfig. 4.9 contains the fix. Thanks, Daniel net/mac80211/debugfs.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c index 4d2aaebd4f97..e546a987a9d3 100644 --- a/net/mac80211/debugfs.c +++ b/net/mac80211/debugfs.c @@ -91,7 +91,7 @@ static const struct file_operations reset_ops = { }; #endif -static const char *hw_flag_names[NUM_IEEE80211_HW_FLAGS + 1] = { +static const char *hw_flag_names[] = { #define FLAG(F) [IEEE80211_HW_##F] = #F FLAG(HAS_RATE_CONTROL), FLAG(RX_INCLUDES_FCS), @@ -125,9 +125,6 @@ static const char *hw_flag_names[NUM_IEEE80211_HW_FLAGS + 1] = { FLAG(TDLS_WIDER_BW), FLAG(SUPPORTS_AMSDU_IN_AMPDU), FLAG(BEACON_TX_STATUS), - - /* keep last for the build bug below */ - (void *)0x1 #undef FLAG }; @@ -147,7 +144,7 @@ static ssize_t hwflags_read(struct file *file, char __user *user_buf, /* fail compilation if somebody adds or removes * a flag without updating the name array above */ - BUILD_BUG_ON(hw_flag_names[NUM_IEEE80211_HW_FLAGS] != (void *)0x1); + BUILD_BUG_ON(ARRAY_SIZE(hw_flag_names) != NUM_IEEE80211_HW_FLAGS); for (i = 0; i < NUM_IEEE80211_HW_FLAGS; i++) { if (test_bit(i, local->hw.flags)) -- 2.14.3

7 years, 4 months

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[Linux-stable-mirror] [PATCH for-3.18.y] perf/core: Fix concurrent sys_perf_event_open() vs. 'move_group' race

by Amit Pundir

From: Peter Zijlstra <peterz(a)infradead.org> commit 321027c1fe77f892f4ea07846aeae08cefbbb290 upstream. Di Shen reported a race between two concurrent sys_perf_event_open() calls where both try and move the same pre-existing software group into a hardware context. The problem is exactly that described in commit: f63a8daa5812 ("perf: Fix event->ctx locking") ... where, while we wait for a ctx->mutex acquisition, the event->ctx relation can have changed under us. That very same commit failed to recognise sys_perf_event_context() as an external access vector to the events and thereby didn't apply the established locking rules correctly. So while one sys_perf_event_open() call is stuck waiting on mutex_lock_double(), the other (which owns said locks) moves the group about. So by the time the former sys_perf_event_open() acquires the locks, the context we've acquired is stale (and possibly dead). Apply the established locking rules as per perf_event_ctx_lock_nested() to the mutex_lock_double() for the 'move_group' case. This obviously means we need to validate state after we acquire the locks. Reported-by: Di Shen (Keen Lab) Tested-by: John Dias <joaodias(a)google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme(a)kernel.org> Cc: Arnaldo Carvalho de Melo <acme(a)redhat.com> Cc: Jiri Olsa <jolsa(a)redhat.com> Cc: Kees Cook <keescook(a)chromium.org> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Min Chong <mchong(a)google.com> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Stephane Eranian <eranian(a)google.com> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vince Weaver <vincent.weaver(a)maine.edu> Fixes: f63a8daa5812 ("perf: Fix event->ctx locking") Link: http://lkml.kernel.org/r/20170106131444.GZ3174@twins.programming.kicks-ass.… Signed-off-by: Ingo Molnar <mingo(a)kernel.org> [bwh: Backported to 3.16: - Use ACCESS_ONCE() instead of READ_ONCE() - Test perf_event::group_flags instead of group_caps - Add the err_locked cleanup block, which we didn't need before - Adjust context] Signed-off-by: Ben Hutchings <ben(a)decadent.org.uk> Signed-off-by: Suren Baghdasaryan <surenb(a)google.com> Signed-off-by: Amit Pundir <amit.pundir(a)linaro.org> --- This upstream patch is featured in recent Android Security bulletin. Picked up this backported patch from android-3.18. Build tested on 3.18.91 kernel/events/core.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 57 insertions(+), 4 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 9b12efcefdf7..de3303aab7d6 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7414,6 +7414,37 @@ static void mutex_lock_double(struct mutex *a, struct mutex *b) mutex_lock_nested(b, SINGLE_DEPTH_NESTING); } +/* + * Variation on perf_event_ctx_lock_nested(), except we take two context + * mutexes. + */ +static struct perf_event_context * +__perf_event_ctx_lock_double(struct perf_event *group_leader, + struct perf_event_context *ctx) +{ + struct perf_event_context *gctx; + +again: + rcu_read_lock(); + gctx = ACCESS_ONCE(group_leader->ctx); + if (!atomic_inc_not_zero(&gctx->refcount)) { + rcu_read_unlock(); + goto again; + } + rcu_read_unlock(); + + mutex_lock_double(&gctx->mutex, &ctx->mutex); + + if (group_leader->ctx != gctx) { + mutex_unlock(&ctx->mutex); + mutex_unlock(&gctx->mutex); + put_ctx(gctx); + goto again; + } + + return gctx; +} + /** * sys_perf_event_open - open a performance event, associate it to a task/cpu * @@ -7626,14 +7657,31 @@ SYSCALL_DEFINE5(perf_event_open, } if (move_group) { - gctx = group_leader->ctx; + gctx = __perf_event_ctx_lock_double(group_leader, ctx); + + /* + * Check if we raced against another sys_perf_event_open() call + * moving the software group underneath us. + */ + if (!(group_leader->group_flags & PERF_GROUP_SOFTWARE)) { + /* + * If someone moved the group out from under us, check + * if this new event wound up on the same ctx, if so + * its the regular !move_group case, otherwise fail. + */ + if (gctx != ctx) { + err = -EINVAL; + goto err_locked; + } else { + perf_event_ctx_unlock(group_leader, gctx); + move_group = 0; + } + } /* * See perf_event_ctx_lock() for comments on the details * of swizzling perf_event::ctx. */ - mutex_lock_double(&gctx->mutex, &ctx->mutex); - perf_remove_from_context(group_leader, false); /* @@ -7674,7 +7722,7 @@ SYSCALL_DEFINE5(perf_event_open, perf_unpin_context(ctx); if (move_group) { - mutex_unlock(&gctx->mutex); + perf_event_ctx_unlock(group_leader, gctx); put_ctx(gctx); } mutex_unlock(&ctx->mutex); @@ -7703,6 +7751,11 @@ SYSCALL_DEFINE5(perf_event_open, fd_install(event_fd, event_file); return event_fd; +err_locked: + if (move_group) + perf_event_ctx_unlock(group_leader, gctx); + mutex_unlock(&ctx->mutex); + fput(event_file); err_context: perf_unpin_context(ctx); put_ctx(ctx); -- 2.7.4

7 years, 4 months

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[Linux-stable-mirror] FAILED: patch "[PATCH] MIPS: Disallow outsized PTRACE_SETREGSET NT_PRFPREG regset" failed to apply to 3.18-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 3.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From c8c5a3a24d395b14447a9a89d61586a913840a3b Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" <macro(a)mips.com> Date: Mon, 11 Dec 2017 22:56:54 +0000 Subject: [PATCH] MIPS: Disallow outsized PTRACE_SETREGSET NT_PRFPREG regset accesses Complement commit c23b3d1a5311 ("MIPS: ptrace: Change GP regset to use correct core dump register layout") and also reject outsized PTRACE_SETREGSET requests to the NT_PRFPREG regset, like with the NT_PRSTATUS regset. Signed-off-by: Maciej W. Rozycki <macro(a)mips.com> Fixes: c23b3d1a5311 ("MIPS: ptrace: Change GP regset to use correct core dump register layout") Cc: James Hogan <james.hogan(a)mips.com> Cc: Paul Burton <Paul.Burton(a)mips.com> Cc: Alex Smith <alex(a)alex-smith.me.uk> Cc: Dave Martin <Dave.Martin(a)arm.com> Cc: linux-mips(a)linux-mips.org Cc: linux-kernel(a)vger.kernel.org Cc: stable(a)vger.kernel.org # v3.17+ Patchwork: https://patchwork.linux-mips.org/patch/17930/ Signed-off-by: Ralf Baechle <ralf(a)linux-mips.org> diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index 256908951a7c..0b23b1ad99e6 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -550,6 +550,9 @@ static int fpr_set(struct task_struct *target, BUG_ON(count % sizeof(elf_fpreg_t)); + if (pos + count > sizeof(elf_fpregset_t)) + return -EIO; + init_fp_ctx(target); if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t))

7 years, 4 months

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[Linux-stable-mirror] FAILED: patch "[PATCH] MIPS: Fix an FCSR access API regression with NT_PRFPREG and" failed to apply to 3.18-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 3.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From be07a6a1188372b6d19a3307ec33211fc9c9439d Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" <macro(a)mips.com> Date: Mon, 11 Dec 2017 22:54:33 +0000 Subject: [PATCH] MIPS: Fix an FCSR access API regression with NT_PRFPREG and MSA Fix a commit 72b22bbad1e7 ("MIPS: Don't assume 64-bit FP registers for FP regset") public API regression, then activated by commit 1db1af84d6df ("MIPS: Basic MSA context switching support"), that caused the FCSR register not to be read or written for CONFIG_CPU_HAS_MSA kernel configurations (regardless of actual presence or absence of the MSA feature in a given processor) with ptrace(2) PTRACE_GETREGSET and PTRACE_SETREGSET requests nor recorded in core dumps. This is because with !CONFIG_CPU_HAS_MSA configurations the whole of `elf_fpregset_t' array is bulk-copied as it is, which includes the FCSR in one half of the last, 33rd slot, whereas with CONFIG_CPU_HAS_MSA configurations array elements are copied individually, and then only the leading 32 FGR slots while the remaining slot is ignored. Correct the code then such that only FGR slots are copied in the respective !MSA and MSA helpers an then the FCSR slot is handled separately in common code. Use `ptrace_setfcr31' to update the FCSR too, so that the read-only mask is respected. Retrieving a correct value of FCSR is important in debugging not only for the human to be able to get the right interpretation of the situation, but for correct operation of GDB as well. This is because the condition code bits in FSCR are used by GDB to determine the location to place a breakpoint at when single-stepping through an FPU branch instruction. If such a breakpoint is placed incorrectly (i.e. with the condition reversed), then it will be missed, likely causing the debuggee to run away from the control of GDB and consequently breaking the process of investigation. Fortunately GDB continues using the older PTRACE_GETFPREGS ptrace(2) request which is unaffected, so the regression only really hits with post-mortem debug sessions using a core dump file, in which case execution, and consequently single-stepping through branches is not possible. Of course core files created by buggy kernels out there will have the value of FCSR recorded clobbered, but such core files cannot be corrected and the person using them simply will have to be aware that the value of FCSR retrieved is not reliable. Which also means we can likely get away without defining a replacement API which would ensure a correct value of FSCR to be retrieved, or none at all. This is based on previous work by Alex Smith, extensively rewritten. Signed-off-by: Alex Smith <alex(a)alex-smith.me.uk> Signed-off-by: James Hogan <james.hogan(a)mips.com> Signed-off-by: Maciej W. Rozycki <macro(a)mips.com> Fixes: 72b22bbad1e7 ("MIPS: Don't assume 64-bit FP registers for FP regset") Cc: Paul Burton <Paul.Burton(a)mips.com> Cc: Dave Martin <Dave.Martin(a)arm.com> Cc: linux-mips(a)linux-mips.org Cc: linux-kernel(a)vger.kernel.org Cc: stable(a)vger.kernel.org # v3.15+ Patchwork: https://patchwork.linux-mips.org/patch/17928/ Signed-off-by: Ralf Baechle <ralf(a)linux-mips.org> diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index 47a01d5f26ea..0a939593ccb7 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -422,7 +422,7 @@ static int gpr64_set(struct task_struct *target, /* * Copy the floating-point context to the supplied NT_PRFPREG buffer, * !CONFIG_CPU_HAS_MSA variant. FP context's general register slots - * correspond 1:1 to buffer slots. + * correspond 1:1 to buffer slots. Only general registers are copied. */ static int fpr_get_fpa(struct task_struct *target, unsigned int *pos, unsigned int *count, @@ -430,13 +430,14 @@ static int fpr_get_fpa(struct task_struct *target, { return user_regset_copyout(pos, count, kbuf, ubuf, &target->thread.fpu, - 0, sizeof(elf_fpregset_t)); + 0, NUM_FPU_REGS * sizeof(elf_fpreg_t)); } /* * Copy the floating-point context to the supplied NT_PRFPREG buffer, * CONFIG_CPU_HAS_MSA variant. Only lower 64 bits of FP context's - * general register slots are copied to buffer slots. + * general register slots are copied to buffer slots. Only general + * registers are copied. */ static int fpr_get_msa(struct task_struct *target, unsigned int *pos, unsigned int *count, @@ -458,20 +459,29 @@ static int fpr_get_msa(struct task_struct *target, return 0; } -/* Copy the floating-point context to the supplied NT_PRFPREG buffer. */ +/* + * Copy the floating-point context to the supplied NT_PRFPREG buffer. + * Choose the appropriate helper for general registers, and then copy + * the FCSR register separately. + */ static int fpr_get(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, void *kbuf, void __user *ubuf) { + const int fcr31_pos = NUM_FPU_REGS * sizeof(elf_fpreg_t); int err; - /* XXX fcr31 */ - if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t)) err = fpr_get_fpa(target, &pos, &count, &kbuf, &ubuf); else err = fpr_get_msa(target, &pos, &count, &kbuf, &ubuf); + if (err) + return err; + + err = user_regset_copyout(&pos, &count, &kbuf, &ubuf, + &target->thread.fpu.fcr31, + fcr31_pos, fcr31_pos + sizeof(u32)); return err; } @@ -479,7 +489,7 @@ static int fpr_get(struct task_struct *target, /* * Copy the supplied NT_PRFPREG buffer to the floating-point context, * !CONFIG_CPU_HAS_MSA variant. Buffer slots correspond 1:1 to FP - * context's general register slots. + * context's general register slots. Only general registers are copied. */ static int fpr_set_fpa(struct task_struct *target, unsigned int *pos, unsigned int *count, @@ -487,13 +497,14 @@ static int fpr_set_fpa(struct task_struct *target, { return user_regset_copyin(pos, count, kbuf, ubuf, &target->thread.fpu, - 0, sizeof(elf_fpregset_t)); + 0, NUM_FPU_REGS * sizeof(elf_fpreg_t)); } /* * Copy the supplied NT_PRFPREG buffer to the floating-point context, * CONFIG_CPU_HAS_MSA variant. Buffer slots are copied to lower 64 - * bits only of FP context's general register slots. + * bits only of FP context's general register slots. Only general + * registers are copied. */ static int fpr_set_msa(struct task_struct *target, unsigned int *pos, unsigned int *count, @@ -518,6 +529,8 @@ static int fpr_set_msa(struct task_struct *target, /* * Copy the supplied NT_PRFPREG buffer to the floating-point context. + * Choose the appropriate helper for general registers, and then copy + * the FCSR register separately. * * We optimize for the case where `count % sizeof(elf_fpreg_t) == 0', * which is supposed to have been guaranteed by the kernel before @@ -530,18 +543,30 @@ static int fpr_set(struct task_struct *target, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { + const int fcr31_pos = NUM_FPU_REGS * sizeof(elf_fpreg_t); + u32 fcr31; int err; BUG_ON(count % sizeof(elf_fpreg_t)); - /* XXX fcr31 */ - init_fp_ctx(target); if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t)) err = fpr_set_fpa(target, &pos, &count, &kbuf, &ubuf); else err = fpr_set_msa(target, &pos, &count, &kbuf, &ubuf); + if (err) + return err; + + if (count > 0) { + err = user_regset_copyin(&pos, &count, &kbuf, &ubuf, + &fcr31, + fcr31_pos, fcr31_pos + sizeof(u32)); + if (err) + return err; + + ptrace_setfcr31(target, fcr31); + } return err; }

7 years, 4 months

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[Linux-stable-mirror] FAILED: patch "[PATCH] MIPS: Consistently handle buffer counter with" failed to apply to 3.18-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 3.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 80b3ffce0196ea50068885d085ff981e4b8396f4 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" <macro(a)mips.com> Date: Mon, 11 Dec 2017 22:53:14 +0000 Subject: [PATCH] MIPS: Consistently handle buffer counter with PTRACE_SETREGSET Update commit d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write") bug and consistently consume all data supplied to `fpr_set_msa' with the ptrace(2) PTRACE_SETREGSET request, such that a zero data buffer counter is returned where insufficient data has been given to fill a whole number of FP general registers. In reality this is not going to happen, as the caller is supposed to only supply data covering a whole number of registers and it is verified in `ptrace_regset' and again asserted in `fpr_set', however structuring code such that the presence of trailing partial FP general register data causes `fpr_set_msa' to return with a non-zero data buffer counter makes it appear that this trailing data will be used if there are subsequent writes made to FP registers, which is going to be the case with the FCSR once the missing write to that register has been fixed. Fixes: d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write") Signed-off-by: Maciej W. Rozycki <macro(a)mips.com> Cc: James Hogan <james.hogan(a)mips.com> Cc: Paul Burton <Paul.Burton(a)mips.com> Cc: Alex Smith <alex(a)alex-smith.me.uk> Cc: Dave Martin <Dave.Martin(a)arm.com> Cc: linux-mips(a)linux-mips.org Cc: linux-kernel(a)vger.kernel.org Cc: stable(a)vger.kernel.org # v4.11+ Patchwork: https://patchwork.linux-mips.org/patch/17927/ Signed-off-by: Ralf Baechle <ralf(a)linux-mips.org> diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index 7fcadaaf330f..47a01d5f26ea 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -504,7 +504,7 @@ static int fpr_set_msa(struct task_struct *target, int err; BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t)); - for (i = 0; i < NUM_FPU_REGS && *count >= sizeof(elf_fpreg_t); i++) { + for (i = 0; i < NUM_FPU_REGS && *count > 0; i++) { err = user_regset_copyin(pos, count, kbuf, ubuf, &fpr_val, i * sizeof(elf_fpreg_t), (i + 1) * sizeof(elf_fpreg_t));

7 years, 4 months

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[Linux-stable-mirror] FAILED: patch "[PATCH] MIPS: Guard against any partial write attempt with" failed to apply to 3.18-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 3.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From dc24d0edf33c3e15099688b6bbdf7bdc24bf6e91 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" <macro(a)mips.com> Date: Mon, 11 Dec 2017 22:52:15 +0000 Subject: [PATCH] MIPS: Guard against any partial write attempt with PTRACE_SETREGSET Complement commit d614fd58a283 ("mips/ptrace: Preserve previous registers for short regset write") and ensure that no partial register write attempt is made with PTRACE_SETREGSET, as we do not preinitialize any temporaries used to hold incoming register data and consequently random data could be written. It is the responsibility of the caller, such as `ptrace_regset', to arrange for writes to span whole registers only, so here we only assert that it has indeed happened. Signed-off-by: Maciej W. Rozycki <macro(a)mips.com> Fixes: 72b22bbad1e7 ("MIPS: Don't assume 64-bit FP registers for FP regset") Cc: James Hogan <james.hogan(a)mips.com> Cc: Paul Burton <Paul.Burton(a)mips.com> Cc: Alex Smith <alex(a)alex-smith.me.uk> Cc: Dave Martin <Dave.Martin(a)arm.com> Cc: linux-mips(a)linux-mips.org Cc: linux-kernel(a)vger.kernel.org Cc: stable(a)vger.kernel.org # v3.15+ Patchwork: https://patchwork.linux-mips.org/patch/17926/ Signed-off-by: Ralf Baechle <ralf(a)linux-mips.org> diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index 62e8ffd9370a..7fcadaaf330f 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -516,7 +516,15 @@ static int fpr_set_msa(struct task_struct *target, return 0; } -/* Copy the supplied NT_PRFPREG buffer to the floating-point context. */ +/* + * Copy the supplied NT_PRFPREG buffer to the floating-point context. + * + * We optimize for the case where `count % sizeof(elf_fpreg_t) == 0', + * which is supposed to have been guaranteed by the kernel before + * calling us, e.g. in `ptrace_regset'. We enforce that requirement, + * so that we can safely avoid preinitializing temporaries for + * partial register writes. + */ static int fpr_set(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, @@ -524,6 +532,8 @@ static int fpr_set(struct task_struct *target, { int err; + BUG_ON(count % sizeof(elf_fpreg_t)); + /* XXX fcr31 */ init_fp_ctx(target);

7 years, 4 months

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[Linux-stable-mirror] FAILED: patch "[PATCH] MIPS: Factor out NT_PRFPREG regset access helpers" failed to apply to 3.18-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 3.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From a03fe72572c12e98f4173f8a535f32468e48b6ec Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" <macro(a)mips.com> Date: Mon, 11 Dec 2017 22:51:35 +0000 Subject: [PATCH] MIPS: Factor out NT_PRFPREG regset access helpers In preparation to fix a commit 72b22bbad1e7 ("MIPS: Don't assume 64-bit FP registers for FP regset") FCSR access regression factor out NT_PRFPREG regset access helpers for the non-MSA and the MSA variants respectively, to avoid having to deal with excessive indentation in the actual fix. No functional change, however use `target->thread.fpu.fpr[0]' rather than `target->thread.fpu.fpr[i]' for FGR holding type size determination as there's no `i' variable to refer to anymore, and for the factored out `i' variable declaration use `unsigned int' rather than `unsigned' as its type, following the common style. Signed-off-by: Maciej W. Rozycki <macro(a)mips.com> Fixes: 72b22bbad1e7 ("MIPS: Don't assume 64-bit FP registers for FP regset") Cc: James Hogan <james.hogan(a)mips.com> Cc: Paul Burton <Paul.Burton(a)mips.com> Cc: Alex Smith <alex(a)alex-smith.me.uk> Cc: Dave Martin <Dave.Martin(a)arm.com> Cc: linux-mips(a)linux-mips.org Cc: linux-kernel(a)vger.kernel.org Cc: stable(a)vger.kernel.org # v3.15+ Patchwork: https://patchwork.linux-mips.org/patch/17925/ Signed-off-by: Ralf Baechle <ralf(a)linux-mips.org> diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index efbd8df8b665..62e8ffd9370a 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -419,25 +419,36 @@ static int gpr64_set(struct task_struct *target, #endif /* CONFIG_64BIT */ -static int fpr_get(struct task_struct *target, - const struct user_regset *regset, - unsigned int pos, unsigned int count, - void *kbuf, void __user *ubuf) +/* + * Copy the floating-point context to the supplied NT_PRFPREG buffer, + * !CONFIG_CPU_HAS_MSA variant. FP context's general register slots + * correspond 1:1 to buffer slots. + */ +static int fpr_get_fpa(struct task_struct *target, + unsigned int *pos, unsigned int *count, + void **kbuf, void __user **ubuf) { - unsigned i; - int err; - u64 fpr_val; - - /* XXX fcr31 */ + return user_regset_copyout(pos, count, kbuf, ubuf, + &target->thread.fpu, + 0, sizeof(elf_fpregset_t)); +} - if (sizeof(target->thread.fpu.fpr[i]) == sizeof(elf_fpreg_t)) - return user_regset_copyout(&pos, &count, &kbuf, &ubuf, - &target->thread.fpu, - 0, sizeof(elf_fpregset_t)); +/* + * Copy the floating-point context to the supplied NT_PRFPREG buffer, + * CONFIG_CPU_HAS_MSA variant. Only lower 64 bits of FP context's + * general register slots are copied to buffer slots. + */ +static int fpr_get_msa(struct task_struct *target, + unsigned int *pos, unsigned int *count, + void **kbuf, void __user **ubuf) +{ + unsigned int i; + u64 fpr_val; + int err; for (i = 0; i < NUM_FPU_REGS; i++) { fpr_val = get_fpr64(&target->thread.fpu.fpr[i], 0); - err = user_regset_copyout(&pos, &count, &kbuf, &ubuf, + err = user_regset_copyout(pos, count, kbuf, ubuf, &fpr_val, i * sizeof(elf_fpreg_t), (i + 1) * sizeof(elf_fpreg_t)); if (err) @@ -447,27 +458,54 @@ static int fpr_get(struct task_struct *target, return 0; } -static int fpr_set(struct task_struct *target, +/* Copy the floating-point context to the supplied NT_PRFPREG buffer. */ +static int fpr_get(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, - const void *kbuf, const void __user *ubuf) + void *kbuf, void __user *ubuf) { - unsigned i; int err; - u64 fpr_val; /* XXX fcr31 */ - init_fp_ctx(target); + if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t)) + err = fpr_get_fpa(target, &pos, &count, &kbuf, &ubuf); + else + err = fpr_get_msa(target, &pos, &count, &kbuf, &ubuf); + + return err; +} - if (sizeof(target->thread.fpu.fpr[i]) == sizeof(elf_fpreg_t)) - return user_regset_copyin(&pos, &count, &kbuf, &ubuf, - &target->thread.fpu, - 0, sizeof(elf_fpregset_t)); +/* + * Copy the supplied NT_PRFPREG buffer to the floating-point context, + * !CONFIG_CPU_HAS_MSA variant. Buffer slots correspond 1:1 to FP + * context's general register slots. + */ +static int fpr_set_fpa(struct task_struct *target, + unsigned int *pos, unsigned int *count, + const void **kbuf, const void __user **ubuf) +{ + return user_regset_copyin(pos, count, kbuf, ubuf, + &target->thread.fpu, + 0, sizeof(elf_fpregset_t)); +} + +/* + * Copy the supplied NT_PRFPREG buffer to the floating-point context, + * CONFIG_CPU_HAS_MSA variant. Buffer slots are copied to lower 64 + * bits only of FP context's general register slots. + */ +static int fpr_set_msa(struct task_struct *target, + unsigned int *pos, unsigned int *count, + const void **kbuf, const void __user **ubuf) +{ + unsigned int i; + u64 fpr_val; + int err; BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t)); - for (i = 0; i < NUM_FPU_REGS && count >= sizeof(elf_fpreg_t); i++) { - err = user_regset_copyin(&pos, &count, &kbuf, &ubuf, + for (i = 0; i < NUM_FPU_REGS && *count >= sizeof(elf_fpreg_t); i++) { + err = user_regset_copyin(pos, count, kbuf, ubuf, &fpr_val, i * sizeof(elf_fpreg_t), (i + 1) * sizeof(elf_fpreg_t)); if (err) @@ -478,6 +516,26 @@ static int fpr_set(struct task_struct *target, return 0; } +/* Copy the supplied NT_PRFPREG buffer to the floating-point context. */ +static int fpr_set(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + const void *kbuf, const void __user *ubuf) +{ + int err; + + /* XXX fcr31 */ + + init_fp_ctx(target); + + if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t)) + err = fpr_set_fpa(target, &pos, &count, &kbuf, &ubuf); + else + err = fpr_set_msa(target, &pos, &count, &kbuf, &ubuf); + + return err; +} + enum mips_regset { REGSET_GPR, REGSET_FPR,

7 years, 4 months

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[Linux-stable-mirror] Patch "KVM: Fix stack-out-of-bounds read in write_mmio" has been added to the 4.9-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled KVM: Fix stack-out-of-bounds read in write_mmio to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: kvm-fix-stack-out-of-bounds-read-in-write_mmio.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From e39d200fa5bf5b94a0948db0dae44c1b73b84a56 Mon Sep 17 00:00:00 2001 From: Wanpeng Li <wanpeng.li(a)hotmail.com> Date: Thu, 14 Dec 2017 17:40:50 -0800 Subject: KVM: Fix stack-out-of-bounds read in write_mmio MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Wanpeng Li <wanpeng.li(a)hotmail.com> commit e39d200fa5bf5b94a0948db0dae44c1b73b84a56 upstream. Reported by syzkaller: BUG: KASAN: stack-out-of-bounds in write_mmio+0x11e/0x270 [kvm] Read of size 8 at addr ffff8803259df7f8 by task syz-executor/32298 CPU: 6 PID: 32298 Comm: syz-executor Tainted: G OE 4.15.0-rc2+ #18 Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016 Call Trace: dump_stack+0xab/0xe1 print_address_description+0x6b/0x290 kasan_report+0x28a/0x370 write_mmio+0x11e/0x270 [kvm] emulator_read_write_onepage+0x311/0x600 [kvm] emulator_read_write+0xef/0x240 [kvm] emulator_fix_hypercall+0x105/0x150 [kvm] em_hypercall+0x2b/0x80 [kvm] x86_emulate_insn+0x2b1/0x1640 [kvm] x86_emulate_instruction+0x39a/0xb90 [kvm] handle_exception+0x1b4/0x4d0 [kvm_intel] vcpu_enter_guest+0x15a0/0x2640 [kvm] kvm_arch_vcpu_ioctl_run+0x549/0x7d0 [kvm] kvm_vcpu_ioctl+0x479/0x880 [kvm] do_vfs_ioctl+0x142/0x9a0 SyS_ioctl+0x74/0x80 entry_SYSCALL_64_fastpath+0x23/0x9a The path of patched vmmcall will patch 3 bytes opcode 0F 01 C1(vmcall) to the guest memory, however, write_mmio tracepoint always prints 8 bytes through *(u64 *)val since kvm splits the mmio access into 8 bytes. This leaks 5 bytes from the kernel stack (CVE-2017-17741). This patch fixes it by just accessing the bytes which we operate on. Before patch: syz-executor-5567 [007] .... 51370.561696: kvm_mmio: mmio write len 3 gpa 0x10 val 0x1ffff10077c1010f After patch: syz-executor-13416 [002] .... 51302.299573: kvm_mmio: mmio write len 3 gpa 0x10 val 0xc1010f Reported-by: Dmitry Vyukov <dvyukov(a)google.com> Reviewed-by: Darren Kenny <darren.kenny(a)oracle.com> Reviewed-by: Marc Zyngier <marc.zyngier(a)arm.com> Tested-by: Marc Zyngier <marc.zyngier(a)arm.com> Cc: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Radim Krčmář <rkrcmar(a)redhat.com> Cc: Marc Zyngier <marc.zyngier(a)arm.com> Cc: Christoffer Dall <christoffer.dall(a)linaro.org> Signed-off-by: Wanpeng Li <wanpeng.li(a)hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/arm/kvm/mmio.c | 6 +++--- arch/x86/kvm/x86.c | 8 ++++---- include/trace/events/kvm.h | 7 +++++-- 3 files changed, 12 insertions(+), 9 deletions(-) --- a/arch/arm/kvm/mmio.c +++ b/arch/arm/kvm/mmio.c @@ -112,7 +112,7 @@ int kvm_handle_mmio_return(struct kvm_vc } trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr, - data); + &data); data = vcpu_data_host_to_guest(vcpu, data, len); vcpu_set_reg(vcpu, vcpu->arch.mmio_decode.rt, data); } @@ -182,14 +182,14 @@ int io_mem_abort(struct kvm_vcpu *vcpu, data = vcpu_data_guest_to_host(vcpu, vcpu_get_reg(vcpu, rt), len); - trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, data); + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, &data); kvm_mmio_write_buf(data_buf, len, data); ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, fault_ipa, len, data_buf); } else { trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, len, - fault_ipa, 0); + fault_ipa, NULL); ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_ipa, len, data_buf); --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4264,7 +4264,7 @@ static int vcpu_mmio_read(struct kvm_vcp addr, n, v)) && kvm_io_bus_read(vcpu, KVM_MMIO_BUS, addr, n, v)) break; - trace_kvm_mmio(KVM_TRACE_MMIO_READ, n, addr, *(u64 *)v); + trace_kvm_mmio(KVM_TRACE_MMIO_READ, n, addr, v); handled += n; addr += n; len -= n; @@ -4517,7 +4517,7 @@ static int read_prepare(struct kvm_vcpu { if (vcpu->mmio_read_completed) { trace_kvm_mmio(KVM_TRACE_MMIO_READ, bytes, - vcpu->mmio_fragments[0].gpa, *(u64 *)val); + vcpu->mmio_fragments[0].gpa, val); vcpu->mmio_read_completed = 0; return 1; } @@ -4539,14 +4539,14 @@ static int write_emulate(struct kvm_vcpu static int write_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes, void *val) { - trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, *(u64 *)val); + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, val); return vcpu_mmio_write(vcpu, gpa, bytes, val); } static int read_exit_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, void *val, int bytes) { - trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, bytes, gpa, 0); + trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, bytes, gpa, NULL); return X86EMUL_IO_NEEDED; } --- a/include/trace/events/kvm.h +++ b/include/trace/events/kvm.h @@ -208,7 +208,7 @@ TRACE_EVENT(kvm_ack_irq, { KVM_TRACE_MMIO_WRITE, "write" } TRACE_EVENT(kvm_mmio, - TP_PROTO(int type, int len, u64 gpa, u64 val), + TP_PROTO(int type, int len, u64 gpa, void *val), TP_ARGS(type, len, gpa, val), TP_STRUCT__entry( @@ -222,7 +222,10 @@ TRACE_EVENT(kvm_mmio, __entry->type = type; __entry->len = len; __entry->gpa = gpa; - __entry->val = val; + __entry->val = 0; + if (val) + memcpy(&__entry->val, val, + min_t(u32, sizeof(__entry->val), len)); ), TP_printk("mmio %s len %u gpa 0x%llx val 0x%llx", Patches currently in stable-queue which might be from wanpeng.li(a)hotmail.com are queue-4.9/kvm-fix-stack-out-of-bounds-read-in-write_mmio.patch

7 years, 4 months

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[Linux-stable-mirror] Patch "KVM: Fix stack-out-of-bounds read in write_mmio" has been added to the 4.4-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled KVM: Fix stack-out-of-bounds read in write_mmio to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: kvm-fix-stack-out-of-bounds-read-in-write_mmio.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From e39d200fa5bf5b94a0948db0dae44c1b73b84a56 Mon Sep 17 00:00:00 2001 From: Wanpeng Li <wanpeng.li(a)hotmail.com> Date: Thu, 14 Dec 2017 17:40:50 -0800 Subject: KVM: Fix stack-out-of-bounds read in write_mmio MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Wanpeng Li <wanpeng.li(a)hotmail.com> commit e39d200fa5bf5b94a0948db0dae44c1b73b84a56 upstream. Reported by syzkaller: BUG: KASAN: stack-out-of-bounds in write_mmio+0x11e/0x270 [kvm] Read of size 8 at addr ffff8803259df7f8 by task syz-executor/32298 CPU: 6 PID: 32298 Comm: syz-executor Tainted: G OE 4.15.0-rc2+ #18 Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016 Call Trace: dump_stack+0xab/0xe1 print_address_description+0x6b/0x290 kasan_report+0x28a/0x370 write_mmio+0x11e/0x270 [kvm] emulator_read_write_onepage+0x311/0x600 [kvm] emulator_read_write+0xef/0x240 [kvm] emulator_fix_hypercall+0x105/0x150 [kvm] em_hypercall+0x2b/0x80 [kvm] x86_emulate_insn+0x2b1/0x1640 [kvm] x86_emulate_instruction+0x39a/0xb90 [kvm] handle_exception+0x1b4/0x4d0 [kvm_intel] vcpu_enter_guest+0x15a0/0x2640 [kvm] kvm_arch_vcpu_ioctl_run+0x549/0x7d0 [kvm] kvm_vcpu_ioctl+0x479/0x880 [kvm] do_vfs_ioctl+0x142/0x9a0 SyS_ioctl+0x74/0x80 entry_SYSCALL_64_fastpath+0x23/0x9a The path of patched vmmcall will patch 3 bytes opcode 0F 01 C1(vmcall) to the guest memory, however, write_mmio tracepoint always prints 8 bytes through *(u64 *)val since kvm splits the mmio access into 8 bytes. This leaks 5 bytes from the kernel stack (CVE-2017-17741). This patch fixes it by just accessing the bytes which we operate on. Before patch: syz-executor-5567 [007] .... 51370.561696: kvm_mmio: mmio write len 3 gpa 0x10 val 0x1ffff10077c1010f After patch: syz-executor-13416 [002] .... 51302.299573: kvm_mmio: mmio write len 3 gpa 0x10 val 0xc1010f Reported-by: Dmitry Vyukov <dvyukov(a)google.com> Reviewed-by: Darren Kenny <darren.kenny(a)oracle.com> Reviewed-by: Marc Zyngier <marc.zyngier(a)arm.com> Tested-by: Marc Zyngier <marc.zyngier(a)arm.com> Cc: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Radim Krčmář <rkrcmar(a)redhat.com> Cc: Marc Zyngier <marc.zyngier(a)arm.com> Cc: Christoffer Dall <christoffer.dall(a)linaro.org> Signed-off-by: Wanpeng Li <wanpeng.li(a)hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/arm/kvm/mmio.c | 6 +++--- arch/x86/kvm/x86.c | 8 ++++---- include/trace/events/kvm.h | 7 +++++-- 3 files changed, 12 insertions(+), 9 deletions(-) --- a/arch/arm/kvm/mmio.c +++ b/arch/arm/kvm/mmio.c @@ -113,7 +113,7 @@ int kvm_handle_mmio_return(struct kvm_vc } trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr, - data); + &data); data = vcpu_data_host_to_guest(vcpu, data, len); vcpu_set_reg(vcpu, vcpu->arch.mmio_decode.rt, data); } @@ -189,14 +189,14 @@ int io_mem_abort(struct kvm_vcpu *vcpu, data = vcpu_data_guest_to_host(vcpu, vcpu_get_reg(vcpu, rt), len); - trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, data); + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, &data); mmio_write_buf(data_buf, len, data); ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, fault_ipa, len, data_buf); } else { trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, len, - fault_ipa, 0); + fault_ipa, NULL); ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_ipa, len, data_buf); --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4114,7 +4114,7 @@ static int vcpu_mmio_read(struct kvm_vcp addr, n, v)) && kvm_io_bus_read(vcpu, KVM_MMIO_BUS, addr, n, v)) break; - trace_kvm_mmio(KVM_TRACE_MMIO_READ, n, addr, *(u64 *)v); + trace_kvm_mmio(KVM_TRACE_MMIO_READ, n, addr, v); handled += n; addr += n; len -= n; @@ -4362,7 +4362,7 @@ static int read_prepare(struct kvm_vcpu { if (vcpu->mmio_read_completed) { trace_kvm_mmio(KVM_TRACE_MMIO_READ, bytes, - vcpu->mmio_fragments[0].gpa, *(u64 *)val); + vcpu->mmio_fragments[0].gpa, val); vcpu->mmio_read_completed = 0; return 1; } @@ -4384,14 +4384,14 @@ static int write_emulate(struct kvm_vcpu static int write_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes, void *val) { - trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, *(u64 *)val); + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, val); return vcpu_mmio_write(vcpu, gpa, bytes, val); } static int read_exit_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, void *val, int bytes) { - trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, bytes, gpa, 0); + trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, bytes, gpa, NULL); return X86EMUL_IO_NEEDED; } --- a/include/trace/events/kvm.h +++ b/include/trace/events/kvm.h @@ -204,7 +204,7 @@ TRACE_EVENT(kvm_ack_irq, { KVM_TRACE_MMIO_WRITE, "write" } TRACE_EVENT(kvm_mmio, - TP_PROTO(int type, int len, u64 gpa, u64 val), + TP_PROTO(int type, int len, u64 gpa, void *val), TP_ARGS(type, len, gpa, val), TP_STRUCT__entry( @@ -218,7 +218,10 @@ TRACE_EVENT(kvm_mmio, __entry->type = type; __entry->len = len; __entry->gpa = gpa; - __entry->val = val; + __entry->val = 0; + if (val) + memcpy(&__entry->val, val, + min_t(u32, sizeof(__entry->val), len)); ), TP_printk("mmio %s len %u gpa 0x%llx val 0x%llx", Patches currently in stable-queue which might be from wanpeng.li(a)hotmail.com are queue-4.4/kvm-fix-stack-out-of-bounds-read-in-write_mmio.patch

7 years, 4 months

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[Linux-stable-mirror] Patch "KVM: Fix stack-out-of-bounds read in write_mmio" has been added to the 4.14-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled KVM: Fix stack-out-of-bounds read in write_mmio to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: kvm-fix-stack-out-of-bounds-read-in-write_mmio.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From e39d200fa5bf5b94a0948db0dae44c1b73b84a56 Mon Sep 17 00:00:00 2001 From: Wanpeng Li <wanpeng.li(a)hotmail.com> Date: Thu, 14 Dec 2017 17:40:50 -0800 Subject: KVM: Fix stack-out-of-bounds read in write_mmio MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Wanpeng Li <wanpeng.li(a)hotmail.com> commit e39d200fa5bf5b94a0948db0dae44c1b73b84a56 upstream. Reported by syzkaller: BUG: KASAN: stack-out-of-bounds in write_mmio+0x11e/0x270 [kvm] Read of size 8 at addr ffff8803259df7f8 by task syz-executor/32298 CPU: 6 PID: 32298 Comm: syz-executor Tainted: G OE 4.15.0-rc2+ #18 Hardware name: LENOVO ThinkCentre M8500t-N000/SHARKBAY, BIOS FBKTC1AUS 02/16/2016 Call Trace: dump_stack+0xab/0xe1 print_address_description+0x6b/0x290 kasan_report+0x28a/0x370 write_mmio+0x11e/0x270 [kvm] emulator_read_write_onepage+0x311/0x600 [kvm] emulator_read_write+0xef/0x240 [kvm] emulator_fix_hypercall+0x105/0x150 [kvm] em_hypercall+0x2b/0x80 [kvm] x86_emulate_insn+0x2b1/0x1640 [kvm] x86_emulate_instruction+0x39a/0xb90 [kvm] handle_exception+0x1b4/0x4d0 [kvm_intel] vcpu_enter_guest+0x15a0/0x2640 [kvm] kvm_arch_vcpu_ioctl_run+0x549/0x7d0 [kvm] kvm_vcpu_ioctl+0x479/0x880 [kvm] do_vfs_ioctl+0x142/0x9a0 SyS_ioctl+0x74/0x80 entry_SYSCALL_64_fastpath+0x23/0x9a The path of patched vmmcall will patch 3 bytes opcode 0F 01 C1(vmcall) to the guest memory, however, write_mmio tracepoint always prints 8 bytes through *(u64 *)val since kvm splits the mmio access into 8 bytes. This leaks 5 bytes from the kernel stack (CVE-2017-17741). This patch fixes it by just accessing the bytes which we operate on. Before patch: syz-executor-5567 [007] .... 51370.561696: kvm_mmio: mmio write len 3 gpa 0x10 val 0x1ffff10077c1010f After patch: syz-executor-13416 [002] .... 51302.299573: kvm_mmio: mmio write len 3 gpa 0x10 val 0xc1010f Reported-by: Dmitry Vyukov <dvyukov(a)google.com> Reviewed-by: Darren Kenny <darren.kenny(a)oracle.com> Reviewed-by: Marc Zyngier <marc.zyngier(a)arm.com> Tested-by: Marc Zyngier <marc.zyngier(a)arm.com> Cc: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Radim Krčmář <rkrcmar(a)redhat.com> Cc: Marc Zyngier <marc.zyngier(a)arm.com> Cc: Christoffer Dall <christoffer.dall(a)linaro.org> Signed-off-by: Wanpeng Li <wanpeng.li(a)hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kvm/x86.c | 8 ++++---- include/trace/events/kvm.h | 7 +++++-- virt/kvm/arm/mmio.c | 6 +++--- 3 files changed, 12 insertions(+), 9 deletions(-) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4362,7 +4362,7 @@ static int vcpu_mmio_read(struct kvm_vcp addr, n, v)) && kvm_io_bus_read(vcpu, KVM_MMIO_BUS, addr, n, v)) break; - trace_kvm_mmio(KVM_TRACE_MMIO_READ, n, addr, *(u64 *)v); + trace_kvm_mmio(KVM_TRACE_MMIO_READ, n, addr, v); handled += n; addr += n; len -= n; @@ -4621,7 +4621,7 @@ static int read_prepare(struct kvm_vcpu { if (vcpu->mmio_read_completed) { trace_kvm_mmio(KVM_TRACE_MMIO_READ, bytes, - vcpu->mmio_fragments[0].gpa, *(u64 *)val); + vcpu->mmio_fragments[0].gpa, val); vcpu->mmio_read_completed = 0; return 1; } @@ -4643,14 +4643,14 @@ static int write_emulate(struct kvm_vcpu static int write_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes, void *val) { - trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, *(u64 *)val); + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, bytes, gpa, val); return vcpu_mmio_write(vcpu, gpa, bytes, val); } static int read_exit_mmio(struct kvm_vcpu *vcpu, gpa_t gpa, void *val, int bytes) { - trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, bytes, gpa, 0); + trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, bytes, gpa, NULL); return X86EMUL_IO_NEEDED; } --- a/include/trace/events/kvm.h +++ b/include/trace/events/kvm.h @@ -211,7 +211,7 @@ TRACE_EVENT(kvm_ack_irq, { KVM_TRACE_MMIO_WRITE, "write" } TRACE_EVENT(kvm_mmio, - TP_PROTO(int type, int len, u64 gpa, u64 val), + TP_PROTO(int type, int len, u64 gpa, void *val), TP_ARGS(type, len, gpa, val), TP_STRUCT__entry( @@ -225,7 +225,10 @@ TRACE_EVENT(kvm_mmio, __entry->type = type; __entry->len = len; __entry->gpa = gpa; - __entry->val = val; + __entry->val = 0; + if (val) + memcpy(&__entry->val, val, + min_t(u32, sizeof(__entry->val), len)); ), TP_printk("mmio %s len %u gpa 0x%llx val 0x%llx", --- a/virt/kvm/arm/mmio.c +++ b/virt/kvm/arm/mmio.c @@ -112,7 +112,7 @@ int kvm_handle_mmio_return(struct kvm_vc } trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr, - data); + &data); data = vcpu_data_host_to_guest(vcpu, data, len); vcpu_set_reg(vcpu, vcpu->arch.mmio_decode.rt, data); } @@ -182,14 +182,14 @@ int io_mem_abort(struct kvm_vcpu *vcpu, data = vcpu_data_guest_to_host(vcpu, vcpu_get_reg(vcpu, rt), len); - trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, data); + trace_kvm_mmio(KVM_TRACE_MMIO_WRITE, len, fault_ipa, &data); kvm_mmio_write_buf(data_buf, len, data); ret = kvm_io_bus_write(vcpu, KVM_MMIO_BUS, fault_ipa, len, data_buf); } else { trace_kvm_mmio(KVM_TRACE_MMIO_READ_UNSATISFIED, len, - fault_ipa, 0); + fault_ipa, NULL); ret = kvm_io_bus_read(vcpu, KVM_MMIO_BUS, fault_ipa, len, data_buf); Patches currently in stable-queue which might be from wanpeng.li(a)hotmail.com are queue-4.14/kvm-fix-stack-out-of-bounds-read-in-write_mmio.patch

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