--- /dev/null
+From 096622104e14d8a1db4860bd557717067a0515d2 Mon Sep 17 00:00:00 2001
+From: Dave Martin <Dave.Martin@arm.com>
+Date: Fri, 18 Aug 2017 16:57:01 +0100
+Subject: arm64: fpsimd: Prevent registers leaking across exec
+
+From: Dave Martin <Dave.Martin@arm.com>
+
+commit 096622104e14d8a1db4860bd557717067a0515d2 upstream.
+
+There are some tricky dependencies between the different stages of
+flushing the FPSIMD register state during exec, and these can race
+with context switch in ways that can cause the old task's regs to
+leak across. In particular, a context switch during the memset() can
+cause some of the task's old FPSIMD registers to reappear.
+
+Disabling preemption for this small window would be no big deal for
+performance: preemption is already disabled for similar scenarios
+like updating the FPSIMD registers in sigreturn.
+
+So, instead of rearranging things in ways that might swap existing
+subtle bugs for new ones, this patch just disables preemption
+around the FPSIMD state flushing so that races of this type can't
+occur here. This brings fpsimd_flush_thread() into line with other
+code paths.
+
+Fixes: 674c242c9323 ("arm64: flush FP/SIMD state correctly after execve()")
+Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
+Signed-off-by: Dave Martin <Dave.Martin@arm.com>
+Signed-off-by: Will Deacon <will.deacon@arm.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+
+For stable only.
+
+3.17.x-4.0.x don't appear active, and this patch isn't sufficient to fix
+them (they would need 674c242c9323 also).
+
+ arch/arm64/kernel/fpsimd.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+--- a/arch/arm64/kernel/fpsimd.c
++++ b/arch/arm64/kernel/fpsimd.c
+@@ -157,9 +157,11 @@ void fpsimd_thread_switch(struct task_st
+
+ void fpsimd_flush_thread(void)
+ {
++ preempt_disable();
+ memset(¤t->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
+ fpsimd_flush_task_state(current);
+ set_thread_flag(TIF_FOREIGN_FPSTATE);
++ preempt_enable();
+ }
+
+ /*
--- /dev/null
+From 1bc0eb0446158cc76562176b80623aa119afee5b Mon Sep 17 00:00:00 2001
+From: Hannes Reinecke <hare@suse.de>
+Date: Fri, 7 Apr 2017 09:34:14 +0200
+Subject: scsi: sg: protect accesses to 'reserved' page array
+
+From: Hannes Reinecke <hare@suse.de>
+
+commit 1bc0eb0446158cc76562176b80623aa119afee5b upstream.
+
+The 'reserved' page array is used as a short-cut for mapping data,
+saving us to allocate pages per request. However, the 'reserved' array
+is only capable of holding one request, so this patch introduces a mutex
+for protect 'sg_fd' against concurrent accesses.
+
+Signed-off-by: Hannes Reinecke <hare@suse.com>
+Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
+Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+[toddpoynor@google.com: backport to 3.18-4.9, fixup for bad ioctl
+SG_SET_FORCE_LOW_DMA code removed in later versions and not modified by
+the original patch.]
+
+Signed-off-by: Hannes Reinecke <hare@suse.com>
+Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
+Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
+Signed-off-by: Todd Poynor <toddpoynor@google.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/scsi/sg.c | 47 ++++++++++++++++++++++++++---------------------
+ 1 file changed, 26 insertions(+), 21 deletions(-)
+
+--- a/drivers/scsi/sg.c
++++ b/drivers/scsi/sg.c
+@@ -153,6 +153,7 @@ typedef struct sg_fd { /* holds the sta
+ struct sg_device *parentdp; /* owning device */
+ wait_queue_head_t read_wait; /* queue read until command done */
+ rwlock_t rq_list_lock; /* protect access to list in req_arr */
++ struct mutex f_mutex; /* protect against changes in this fd */
+ int timeout; /* defaults to SG_DEFAULT_TIMEOUT */
+ int timeout_user; /* defaults to SG_DEFAULT_TIMEOUT_USER */
+ Sg_scatter_hold reserve; /* buffer held for this file descriptor */
+@@ -166,6 +167,7 @@ typedef struct sg_fd { /* holds the sta
+ unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
+ char keep_orphan; /* 0 -> drop orphan (def), 1 -> keep for read() */
+ char mmap_called; /* 0 -> mmap() never called on this fd */
++ char res_in_use; /* 1 -> 'reserve' array in use */
+ struct kref f_ref;
+ struct execute_work ew;
+ } Sg_fd;
+@@ -209,7 +211,6 @@ static void sg_remove_sfp(struct kref *)
+ static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
+ static Sg_request *sg_add_request(Sg_fd * sfp);
+ static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
+-static int sg_res_in_use(Sg_fd * sfp);
+ static Sg_device *sg_get_dev(int dev);
+ static void sg_device_destroy(struct kref *kref);
+
+@@ -625,6 +626,7 @@ sg_write(struct file *filp, const char _
+ }
+ buf += SZ_SG_HEADER;
+ __get_user(opcode, buf);
++ mutex_lock(&sfp->f_mutex);
+ if (sfp->next_cmd_len > 0) {
+ cmd_size = sfp->next_cmd_len;
+ sfp->next_cmd_len = 0; /* reset so only this write() effected */
+@@ -633,6 +635,7 @@ sg_write(struct file *filp, const char _
+ if ((opcode >= 0xc0) && old_hdr.twelve_byte)
+ cmd_size = 12;
+ }
++ mutex_unlock(&sfp->f_mutex);
+ SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
+ "sg_write: scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
+ /* Determine buffer size. */
+@@ -732,7 +735,7 @@ sg_new_write(Sg_fd *sfp, struct file *fi
+ sg_remove_request(sfp, srp);
+ return -EINVAL; /* either MMAP_IO or DIRECT_IO (not both) */
+ }
+- if (sg_res_in_use(sfp)) {
++ if (sfp->res_in_use) {
+ sg_remove_request(sfp, srp);
+ return -EBUSY; /* reserve buffer already being used */
+ }
+@@ -902,7 +905,7 @@ sg_ioctl(struct file *filp, unsigned int
+ return result;
+ if (val) {
+ sfp->low_dma = 1;
+- if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
++ if ((0 == sfp->low_dma) && !sfp->res_in_use) {
+ val = (int) sfp->reserve.bufflen;
+ sg_remove_scat(sfp, &sfp->reserve);
+ sg_build_reserve(sfp, val);
+@@ -977,12 +980,18 @@ sg_ioctl(struct file *filp, unsigned int
+ return -EINVAL;
+ val = min_t(int, val,
+ max_sectors_bytes(sdp->device->request_queue));
++ mutex_lock(&sfp->f_mutex);
+ if (val != sfp->reserve.bufflen) {
+- if (sg_res_in_use(sfp) || sfp->mmap_called)
++ if (sfp->mmap_called ||
++ sfp->res_in_use) {
++ mutex_unlock(&sfp->f_mutex);
+ return -EBUSY;
++ }
++
+ sg_remove_scat(sfp, &sfp->reserve);
+ sg_build_reserve(sfp, val);
+ }
++ mutex_unlock(&sfp->f_mutex);
+ return 0;
+ case SG_GET_RESERVED_SIZE:
+ val = min_t(int, sfp->reserve.bufflen,
+@@ -1737,13 +1746,22 @@ sg_start_req(Sg_request *srp, unsigned c
+ md = &map_data;
+
+ if (md) {
+- if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
++ mutex_lock(&sfp->f_mutex);
++ if (dxfer_len <= rsv_schp->bufflen &&
++ !sfp->res_in_use) {
++ sfp->res_in_use = 1;
+ sg_link_reserve(sfp, srp, dxfer_len);
+- else {
++ } else if ((hp->flags & SG_FLAG_MMAP_IO) && sfp->res_in_use) {
++ mutex_unlock(&sfp->f_mutex);
++ return -EBUSY;
++ } else {
+ res = sg_build_indirect(req_schp, sfp, dxfer_len);
+- if (res)
++ if (res) {
++ mutex_unlock(&sfp->f_mutex);
+ return res;
++ }
+ }
++ mutex_unlock(&sfp->f_mutex);
+
+ md->pages = req_schp->pages;
+ md->page_order = req_schp->page_order;
+@@ -2145,6 +2163,7 @@ sg_add_sfp(Sg_device * sdp)
+ rwlock_init(&sfp->rq_list_lock);
+
+ kref_init(&sfp->f_ref);
++ mutex_init(&sfp->f_mutex);
+ sfp->timeout = SG_DEFAULT_TIMEOUT;
+ sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
+ sfp->force_packid = SG_DEF_FORCE_PACK_ID;
+@@ -2220,20 +2239,6 @@ sg_remove_sfp(struct kref *kref)
+ schedule_work(&sfp->ew.work);
+ }
+
+-static int
+-sg_res_in_use(Sg_fd * sfp)
+-{
+- const Sg_request *srp;
+- unsigned long iflags;
+-
+- read_lock_irqsave(&sfp->rq_list_lock, iflags);
+- for (srp = sfp->headrp; srp; srp = srp->nextrp)
+- if (srp->res_used)
+- break;
+- read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
+- return srp ? 1 : 0;
+-}
+-
+ #ifdef CONFIG_SCSI_PROC_FS
+ static int
+ sg_idr_max_id(int id, void *p, void *data)
projects / thirdparty / kernel / stable-queue.git / commitdiff
