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[Linux-stable-mirror] Patch "ALSA: aloop: Release cable upon open error path" has been added to the 3.18-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: aloop: Release cable upon open error path to the 3.18-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: alsa-aloop-release-cable-upon-open-error-path.patch and it can be found in the queue-3.18 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 9685347aa0a5c2869058ca6ab79fd8e93084a67f Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Fri, 5 Jan 2018 16:09:47 +0100 Subject: ALSA: aloop: Release cable upon open error path From: Takashi Iwai <tiwai(a)suse.de> commit 9685347aa0a5c2869058ca6ab79fd8e93084a67f upstream. The aloop runtime object and its assignment in the cable are left even when opening a substream fails. This doesn't mean any memory leak, but it still keeps the invalid pointer that may be referred by the another side of the cable spontaneously, which is a potential Oops cause. Clean up the cable assignment and the empty cable upon the error path properly. Fixes: 597603d615d2 ("ALSA: introduce the snd-aloop module for the PCM loopback") Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/drivers/aloop.c | 38 +++++++++++++++++++++++++------------- 1 file changed, 25 insertions(+), 13 deletions(-) --- a/sound/drivers/aloop.c +++ b/sound/drivers/aloop.c @@ -659,12 +659,31 @@ static int rule_channels(struct snd_pcm_ return snd_interval_refine(hw_param_interval(params, rule->var), &t); } +static void free_cable(struct snd_pcm_substream *substream) +{ + struct loopback *loopback = substream->private_data; + int dev = get_cable_index(substream); + struct loopback_cable *cable; + + cable = loopback->cables[substream->number][dev]; + if (!cable) + return; + if (cable->streams[!substream->stream]) { + /* other stream is still alive */ + cable->streams[substream->stream] = NULL; + } else { + /* free the cable */ + loopback->cables[substream->number][dev] = NULL; + kfree(cable); + } +} + static int loopback_open(struct snd_pcm_substream *substream) { struct snd_pcm_runtime *runtime = substream->runtime; struct loopback *loopback = substream->private_data; struct loopback_pcm *dpcm; - struct loopback_cable *cable; + struct loopback_cable *cable = NULL; int err = 0; int dev = get_cable_index(substream); @@ -683,7 +702,6 @@ static int loopback_open(struct snd_pcm_ if (!cable) { cable = kzalloc(sizeof(*cable), GFP_KERNEL); if (!cable) { - kfree(dpcm); err = -ENOMEM; goto unlock; } @@ -725,6 +743,10 @@ static int loopback_open(struct snd_pcm_ else runtime->hw = cable->hw; unlock: + if (err < 0) { + free_cable(substream); + kfree(dpcm); + } mutex_unlock(&loopback->cable_lock); return err; } @@ -733,20 +755,10 @@ static int loopback_close(struct snd_pcm { struct loopback *loopback = substream->private_data; struct loopback_pcm *dpcm = substream->runtime->private_data; - struct loopback_cable *cable; - int dev = get_cable_index(substream); loopback_timer_stop(dpcm); mutex_lock(&loopback->cable_lock); - cable = loopback->cables[substream->number][dev]; - if (cable->streams[!substream->stream]) { - /* other stream is still alive */ - cable->streams[substream->stream] = NULL; - } else { - /* free the cable */ - loopback->cables[substream->number][dev] = NULL; - kfree(cable); - } + free_cable(substream); mutex_unlock(&loopback->cable_lock); return 0; } Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-3.18/alsa-pcm-remove-incorrect-snd_bug_on-usages.patch queue-3.18/alsa-aloop-fix-inconsistent-format-due-to-incomplete-rule.patch queue-3.18/alsa-pcm-add-missing-error-checks-in-oss-emulation-plugin-builder.patch queue-3.18/alsa-pcm-abort-properly-at-pending-signal-in-oss-read-write-loops.patch queue-3.18/alsa-pcm-allow-aborting-mutex-lock-at-oss-read-write-loops.patch queue-3.18/alsa-aloop-fix-racy-hw-constraints-adjustment.patch queue-3.18/alsa-aloop-release-cable-upon-open-error-path.patch

7 years, 1 month

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[Linux-stable-mirror] Patch "ALSA: pcm: Abort properly at pending signal in OSS read/write loops" has been added to the 3.18-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: pcm: Abort properly at pending signal in OSS read/write loops to the 3.18-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: alsa-pcm-abort-properly-at-pending-signal-in-oss-read-write-loops.patch and it can be found in the queue-3.18 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 29159a4ed7044c52e3e2cf1a9fb55cec4745c60b Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Mon, 8 Jan 2018 13:58:31 +0100 Subject: ALSA: pcm: Abort properly at pending signal in OSS read/write loops From: Takashi Iwai <tiwai(a)suse.de> commit 29159a4ed7044c52e3e2cf1a9fb55cec4745c60b upstream. The loops for read and write in PCM OSS emulation have no proper check of pending signals, and they keep processing even after user tries to break. This results in a very long delay, often seen as RCU stall when a huge unprocessed bytes remain queued. The bug could be easily triggered by syzkaller. As a simple workaround, this patch adds the proper check of pending signals and aborts the loop appropriately. Reported-by: syzbot+993cb4cfcbbff3947c21(a)syzkaller.appspotmail.com Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/core/oss/pcm_oss.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -1417,6 +1417,10 @@ static ssize_t snd_pcm_oss_write1(struct tmp != runtime->oss.period_bytes) break; } + if (signal_pending(current)) { + tmp = -ERESTARTSYS; + goto err; + } } mutex_unlock(&runtime->oss.params_lock); return xfer; @@ -1502,6 +1506,10 @@ static ssize_t snd_pcm_oss_read1(struct bytes -= tmp; xfer += tmp; } + if (signal_pending(current)) { + tmp = -ERESTARTSYS; + goto err; + } } mutex_unlock(&runtime->oss.params_lock); return xfer; Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-3.18/alsa-pcm-remove-incorrect-snd_bug_on-usages.patch queue-3.18/alsa-aloop-fix-inconsistent-format-due-to-incomplete-rule.patch queue-3.18/alsa-pcm-add-missing-error-checks-in-oss-emulation-plugin-builder.patch queue-3.18/alsa-pcm-abort-properly-at-pending-signal-in-oss-read-write-loops.patch queue-3.18/alsa-pcm-allow-aborting-mutex-lock-at-oss-read-write-loops.patch queue-3.18/alsa-aloop-fix-racy-hw-constraints-adjustment.patch queue-3.18/alsa-aloop-release-cable-upon-open-error-path.patch

7 years, 1 month

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[Linux-stable-mirror] Patch "ALSA: aloop: Fix racy hw constraints adjustment" has been added to the 3.18-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: aloop: Fix racy hw constraints adjustment to the 3.18-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: alsa-aloop-fix-racy-hw-constraints-adjustment.patch and it can be found in the queue-3.18 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 898dfe4687f460ba337a01c11549f87269a13fa2 Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Thu, 4 Jan 2018 17:38:54 +0100 Subject: ALSA: aloop: Fix racy hw constraints adjustment From: Takashi Iwai <tiwai(a)suse.de> commit 898dfe4687f460ba337a01c11549f87269a13fa2 upstream. The aloop driver tries to update the hw constraints of the connected target on the cable of the opened PCM substream. This is done by adding the extra hw constraints rules referring to the substream runtime->hw fields, while the other substream may update the runtime hw of another side on the fly. This is, however, racy and may result in the inconsistent values when both PCM streams perform the prepare concurrently. One of the reason is that it overwrites the other's runtime->hw field; which is not only racy but also broken when it's called before the open of another side finishes. And, since the reference to runtime->hw isn't protected, the concurrent write may give the partial value update and become inconsistent. This patch is an attempt to fix and clean up: - The prepare doesn't change the runtime->hw of other side any longer, but only update the cable->hw that is referred commonly. - The extra rules refer to the loopback_pcm object instead of the runtime->hw. The actual hw is deduced from cable->hw. - The extra rules take the cable_lock to protect against the race. Fixes: b1c73fc8e697 ("ALSA: snd-aloop: Fix hw_params restrictions and checking") Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/drivers/aloop.c | 51 ++++++++++++++++++++------------------------------ 1 file changed, 21 insertions(+), 30 deletions(-) --- a/sound/drivers/aloop.c +++ b/sound/drivers/aloop.c @@ -307,19 +307,6 @@ static int loopback_trigger(struct snd_p return 0; } -static void params_change_substream(struct loopback_pcm *dpcm, - struct snd_pcm_runtime *runtime) -{ - struct snd_pcm_runtime *dst_runtime; - - if (dpcm == NULL || dpcm->substream == NULL) - return; - dst_runtime = dpcm->substream->runtime; - if (dst_runtime == NULL) - return; - dst_runtime->hw = dpcm->cable->hw; -} - static void params_change(struct snd_pcm_substream *substream) { struct snd_pcm_runtime *runtime = substream->runtime; @@ -331,10 +318,6 @@ static void params_change(struct snd_pcm cable->hw.rate_max = runtime->rate; cable->hw.channels_min = runtime->channels; cable->hw.channels_max = runtime->channels; - params_change_substream(cable->streams[SNDRV_PCM_STREAM_PLAYBACK], - runtime); - params_change_substream(cable->streams[SNDRV_PCM_STREAM_CAPTURE], - runtime); } static int loopback_prepare(struct snd_pcm_substream *substream) @@ -622,24 +605,29 @@ static unsigned int get_cable_index(stru static int rule_format(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule) { - - struct snd_pcm_hardware *hw = rule->private; + struct loopback_pcm *dpcm = rule->private; + struct loopback_cable *cable = dpcm->cable; struct snd_mask m; snd_mask_none(&m); - m.bits[0] = (u_int32_t)hw->formats; - m.bits[1] = (u_int32_t)(hw->formats >> 32); + mutex_lock(&dpcm->loopback->cable_lock); + m.bits[0] = (u_int32_t)cable->hw.formats; + m.bits[1] = (u_int32_t)(cable->hw.formats >> 32); + mutex_unlock(&dpcm->loopback->cable_lock); return snd_mask_refine(hw_param_mask(params, rule->var), &m); } static int rule_rate(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule) { - struct snd_pcm_hardware *hw = rule->private; + struct loopback_pcm *dpcm = rule->private; + struct loopback_cable *cable = dpcm->cable; struct snd_interval t; - t.min = hw->rate_min; - t.max = hw->rate_max; + mutex_lock(&dpcm->loopback->cable_lock); + t.min = cable->hw.rate_min; + t.max = cable->hw.rate_max; + mutex_unlock(&dpcm->loopback->cable_lock); t.openmin = t.openmax = 0; t.integer = 0; return snd_interval_refine(hw_param_interval(params, rule->var), &t); @@ -648,11 +636,14 @@ static int rule_rate(struct snd_pcm_hw_p static int rule_channels(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule) { - struct snd_pcm_hardware *hw = rule->private; + struct loopback_pcm *dpcm = rule->private; + struct loopback_cable *cable = dpcm->cable; struct snd_interval t; - t.min = hw->channels_min; - t.max = hw->channels_max; + mutex_lock(&dpcm->loopback->cable_lock); + t.min = cable->hw.channels_min; + t.max = cable->hw.channels_max; + mutex_unlock(&dpcm->loopback->cable_lock); t.openmin = t.openmax = 0; t.integer = 0; return snd_interval_refine(hw_param_interval(params, rule->var), &t); @@ -718,19 +709,19 @@ static int loopback_open(struct snd_pcm_ /* are cached -> they do not reflect the actual state */ err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT, - rule_format, &runtime->hw, + rule_format, dpcm, SNDRV_PCM_HW_PARAM_FORMAT, -1); if (err < 0) goto unlock; err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE, - rule_rate, &runtime->hw, + rule_rate, dpcm, SNDRV_PCM_HW_PARAM_RATE, -1); if (err < 0) goto unlock; err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS, - rule_channels, &runtime->hw, + rule_channels, dpcm, SNDRV_PCM_HW_PARAM_CHANNELS, -1); if (err < 0) goto unlock; Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-3.18/alsa-pcm-remove-incorrect-snd_bug_on-usages.patch queue-3.18/alsa-aloop-fix-inconsistent-format-due-to-incomplete-rule.patch queue-3.18/alsa-pcm-add-missing-error-checks-in-oss-emulation-plugin-builder.patch queue-3.18/alsa-pcm-abort-properly-at-pending-signal-in-oss-read-write-loops.patch queue-3.18/alsa-pcm-allow-aborting-mutex-lock-at-oss-read-write-loops.patch queue-3.18/alsa-aloop-fix-racy-hw-constraints-adjustment.patch queue-3.18/alsa-aloop-release-cable-upon-open-error-path.patch

7 years, 1 month

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[Linux-stable-mirror] Patch "ALSA: aloop: Fix inconsistent format due to incomplete rule" has been added to the 3.18-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled ALSA: aloop: Fix inconsistent format due to incomplete rule to the 3.18-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: alsa-aloop-fix-inconsistent-format-due-to-incomplete-rule.patch and it can be found in the queue-3.18 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 b088b53e20c7d09b5ab84c5688e609f478e5c417 Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai(a)suse.de> Date: Fri, 5 Jan 2018 16:15:33 +0100 Subject: ALSA: aloop: Fix inconsistent format due to incomplete rule From: Takashi Iwai <tiwai(a)suse.de> commit b088b53e20c7d09b5ab84c5688e609f478e5c417 upstream. The extra hw constraint rule for the formats the aloop driver introduced has a slight flaw, where it doesn't return a positive value when the mask got changed. It came from the fact that it's basically a copy&paste from snd_hw_constraint_mask64(). The original code is supposed to be a single-shot and it modifies the mask bits only once and never after, while what we need for aloop is the dynamic hw rule that limits the mask bits. This difference results in the inconsistent state, as the hw_refine doesn't apply the dependencies fully. The worse and surprisingly result is that it causes a crash in OSS emulation when multiple full-duplex reads/writes are performed concurrently (I leave why it triggers Oops to readers as a homework). For fixing this, replace a few open-codes with the standard snd_mask_*() macros. Reported-by: syzbot+3902b5220e8ca27889ca(a)syzkaller.appspotmail.com Fixes: b1c73fc8e697 ("ALSA: snd-aloop: Fix hw_params restrictions and checking") Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- sound/drivers/aloop.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) --- a/sound/drivers/aloop.c +++ b/sound/drivers/aloop.c @@ -39,6 +39,7 @@ #include <sound/core.h> #include <sound/control.h> #include <sound/pcm.h> +#include <sound/pcm_params.h> #include <sound/info.h> #include <sound/initval.h> @@ -623,14 +624,12 @@ static int rule_format(struct snd_pcm_hw { struct snd_pcm_hardware *hw = rule->private; - struct snd_mask *maskp = hw_param_mask(params, rule->var); + struct snd_mask m; - maskp->bits[0] &= (u_int32_t)hw->formats; - maskp->bits[1] &= (u_int32_t)(hw->formats >> 32); - memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */ - if (! maskp->bits[0] && ! maskp->bits[1]) - return -EINVAL; - return 0; + snd_mask_none(&m); + m.bits[0] = (u_int32_t)hw->formats; + m.bits[1] = (u_int32_t)(hw->formats >> 32); + return snd_mask_refine(hw_param_mask(params, rule->var), &m); } static int rule_rate(struct snd_pcm_hw_params *params, Patches currently in stable-queue which might be from tiwai(a)suse.de are queue-3.18/alsa-pcm-remove-incorrect-snd_bug_on-usages.patch queue-3.18/alsa-aloop-fix-inconsistent-format-due-to-incomplete-rule.patch queue-3.18/alsa-pcm-add-missing-error-checks-in-oss-emulation-plugin-builder.patch queue-3.18/alsa-pcm-abort-properly-at-pending-signal-in-oss-read-write-loops.patch queue-3.18/alsa-pcm-allow-aborting-mutex-lock-at-oss-read-write-loops.patch queue-3.18/alsa-aloop-fix-racy-hw-constraints-adjustment.patch queue-3.18/alsa-aloop-release-cable-upon-open-error-path.patch

7 years, 1 month

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[Linux-stable-mirror] [PATCH v2 4/7] pipe: fix off-by-one error when checking buffer limits

by Eric Biggers

From: Eric Biggers <ebiggers(a)google.com> With pipe-user-pages-hard set to 'N', users were actually only allowed up to 'N - 1' buffers; and likewise for pipe-user-pages-soft. Fix this to allow up to 'N' buffers, as would be expected. Fixes: b0b91d18e2e9 ("pipe: fix limit checking in pipe_set_size()") Cc: stable(a)vger.kernel.org Acked-by: Willy Tarreau <w(a)1wt.eu> Signed-off-by: Eric Biggers <ebiggers(a)google.com> --- fs/pipe.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/pipe.c b/fs/pipe.c index 847ecc388820..9f20e7128578 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -605,12 +605,12 @@ static unsigned long account_pipe_buffers(struct user_struct *user, static bool too_many_pipe_buffers_soft(unsigned long user_bufs) { - return pipe_user_pages_soft && user_bufs >= pipe_user_pages_soft; + return pipe_user_pages_soft && user_bufs > pipe_user_pages_soft; } static bool too_many_pipe_buffers_hard(unsigned long user_bufs) { - return pipe_user_pages_hard && user_bufs >= pipe_user_pages_hard; + return pipe_user_pages_hard && user_bufs > pipe_user_pages_hard; } static bool is_unprivileged_user(void) -- 2.15.1

7 years, 1 month

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[Linux-stable-mirror] [PATCH v2 3/7] pipe: actually allow root to exceed the pipe buffer limits

by Eric Biggers

From: Eric Biggers <ebiggers(a)google.com> pipe-user-pages-hard and pipe-user-pages-soft are only supposed to apply to unprivileged users, as documented in both Documentation/sysctl/fs.txt and the pipe(7) man page. However, the capabilities are actually only checked when increasing a pipe's size using F_SETPIPE_SZ, not when creating a new pipe. Therefore, if pipe-user-pages-hard has been set, the root user can run into it and be unable to create pipes. Similarly, if pipe-user-pages-soft has been set, the root user can run into it and have their pipes limited to 1 page each. Fix this by allowing the privileged override in both cases. Fixes: 759c01142a5d ("pipe: limit the per-user amount of pages allocated in pipes") Cc: stable(a)vger.kernel.org Signed-off-by: Eric Biggers <ebiggers(a)google.com> --- fs/pipe.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/pipe.c b/fs/pipe.c index d0dec5e7ef33..847ecc388820 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -613,6 +613,11 @@ static bool too_many_pipe_buffers_hard(unsigned long user_bufs) return pipe_user_pages_hard && user_bufs >= pipe_user_pages_hard; } +static bool is_unprivileged_user(void) +{ + return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN); +} + struct pipe_inode_info *alloc_pipe_info(void) { struct pipe_inode_info *pipe; @@ -629,12 +634,12 @@ struct pipe_inode_info *alloc_pipe_info(void) user_bufs = account_pipe_buffers(user, 0, pipe_bufs); - if (too_many_pipe_buffers_soft(user_bufs)) { + if (too_many_pipe_buffers_soft(user_bufs) && is_unprivileged_user()) { user_bufs = account_pipe_buffers(user, pipe_bufs, 1); pipe_bufs = 1; } - if (too_many_pipe_buffers_hard(user_bufs)) + if (too_many_pipe_buffers_hard(user_bufs) && is_unprivileged_user()) goto out_revert_acct; pipe->bufs = kcalloc(pipe_bufs, sizeof(struct pipe_buffer), @@ -1065,7 +1070,7 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg) if (nr_pages > pipe->buffers && (too_many_pipe_buffers_hard(user_bufs) || too_many_pipe_buffers_soft(user_bufs)) && - !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) { + is_unprivileged_user()) { ret = -EPERM; goto out_revert_acct; } -- 2.15.1

7 years, 1 month

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[Linux-stable-mirror] [PATCH 3.18] MIPS: Disallow outsized PTRACE_SETREGSET NT_PRFPREG regset accesses

by Maciej W. Rozycki

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> --- Hi, This is a (mechanically regenerated) version of commit c8c5a3a24d39 for 3.18-stable and before. No functional changes. Please apply. Maciej --- arch/mips/kernel/ptrace.c | 3 +++ 1 file changed, 3 insertions(+) linux-mips-nt-prfpreg-size.diff Index: linux-stable-el/arch/mips/kernel/ptrace.c =================================================================== --- linux-stable-el.orig/arch/mips/kernel/ptrace.c 2018-01-10 20:11:52.000000000 +0000 +++ linux-stable-el/arch/mips/kernel/ptrace.c 2018-01-10 20:13:16.212944000 +0000 @@ -530,6 +530,9 @@ static int fpr_set(struct task_struct *t BUG_ON(count % sizeof(elf_fpreg_t)); + if (pos + count > sizeof(elf_fpregset_t)) + return -EIO; + if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t)) err = fpr_set_fpa(target, &pos, &count, &kbuf, &ubuf); else

7 years, 1 month

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[Linux-stable-mirror] [PATCH 3.18] MIPS: Fix an FCSR access API regression with NT_PRFPREG and MSA

by Maciej W. Rozycki

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> --- Hi, This is a version of commit be07a6a11883 for 3.18-stable and before. It updates code added like this: - ptrace_setfcr31(target, fcr31); + target->thread.fpu.fcr31 = fcr31 & ~FPU_CSR_ALL_X; because there is no `ptrace_setfcr31' helper in 3.18. This is equivalent to the original commit in terms of functionality as at version 3.18. Please apply. Maciej --- arch/mips/kernel/ptrace.c | 47 +++++++++++++++++++++++++++++++++++----------- 1 file changed, 36 insertions(+), 11 deletions(-) linux-mips-nt-prfpreg-fcsr.diff Index: linux-stable-el/arch/mips/kernel/ptrace.c =================================================================== --- linux-stable-el.orig/arch/mips/kernel/ptrace.c 2018-01-10 20:03:43.000000000 +0000 +++ linux-stable-el/arch/mips/kernel/ptrace.c 2018-01-10 20:11:52.407204000 +0000 @@ -403,7 +403,7 @@ static int gpr64_set(struct task_struct /* * 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, @@ -411,13 +411,14 @@ static int fpr_get_fpa(struct task_struc { 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, @@ -439,20 +440,29 @@ static int fpr_get_msa(struct task_struc 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; } @@ -460,7 +470,7 @@ static int fpr_get(struct task_struct *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. + * 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, @@ -468,13 +478,14 @@ static int fpr_set_fpa(struct task_struc { 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, @@ -499,6 +510,8 @@ static int fpr_set_msa(struct task_struc /* * 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 @@ -511,16 +524,28 @@ static int fpr_set(struct task_struct *t 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 */ - 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; + + target->thread.fpu.fcr31 = fcr31 & ~FPU_CSR_ALL_X; + } return err; }

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[Linux-stable-mirror] [PATCH 3.18] MIPS: Consistently handle buffer counter with PTRACE_SETREGSET

by Maciej W. Rozycki

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> --- Hi, This is a (mechanically regenerated) version of commit 80b3ffce0196 for 3.18-stable and before. No functional changes. Please apply. Maciej --- arch/mips/kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) linux-mips-nt-prfpreg-count.diff Index: linux-stable-el/arch/mips/kernel/ptrace.c =================================================================== --- linux-stable-el.orig/arch/mips/kernel/ptrace.c 2018-01-10 20:27:12.485956000 +0000 +++ linux-stable-el/arch/mips/kernel/ptrace.c 2018-01-10 20:27:13.744971000 +0000 @@ -485,7 +485,7 @@ static int fpr_set_msa(struct task_struc 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, 1 month

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[Linux-stable-mirror] [PATCH 3.18] MIPS: Guard against any partial write attempt with PTRACE_SETREGSET

by Maciej W. Rozycki

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> --- Hi, This is a (mechanically regenerated) version of commit dc24d0edf33c for 3.18-stable and before. No functional changes. Please apply. Maciej --- arch/mips/kernel/ptrace.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) linux-mips-nt-prfpreg-size-bug.diff Index: linux-stable-el/arch/mips/kernel/ptrace.c =================================================================== --- linux-stable-el.orig/arch/mips/kernel/ptrace.c 2018-01-10 20:13:31.900045000 +0000 +++ linux-stable-el/arch/mips/kernel/ptrace.c 2018-01-10 20:13:33.337064000 +0000 @@ -497,7 +497,15 @@ static int fpr_set_msa(struct task_struc 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, @@ -505,6 +513,8 @@ static int fpr_set(struct task_struct *t { int err; + BUG_ON(count % sizeof(elf_fpreg_t)); + /* XXX fcr31 */ if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t))

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