diff --git a/kernel.spec b/kernel.spec index 47152d0..ffa0838 100644 --- a/kernel.spec +++ b/kernel.spec @@ -639,6 +639,10 @@ Patch656: unix-correctly-track-in-flight-fds-in-sending-proces.patch Patch657: 0001-Test-ata-fix.patch Patch658: nouveau-displayoff-fix.patch + +#Mitigates CVE-2013-4312 rhbz 1313428 1313433 +Patch659: pipe-limit-the-per-user-amount-of-pages-allocated-in.patch + # END OF PATCH DEFINITIONS %endif @@ -1340,6 +1344,10 @@ ApplyPatch unix-correctly-track-in-flight-fds-in-sending-proces.patch ApplyPatch 0001-Test-ata-fix.patch ApplyPatch nouveau-displayoff-fix.patch + +#Mitigates CVE-2013-4312 rhbz 1313428 1313433 +ApplyPatch pipe-limit-the-per-user-amount-of-pages-allocated-in.patch + # END OF PATCH APPLICATIONS %endif @@ -2189,6 +2197,9 @@ fi # # %changelog +* Wed Mar 02 2016 Josh Boyer +- pipe: limit the per-user amount of pages allocated in pipes (rhbz 1313428 1313433) + * Sat Feb 27 2016 Peter Robinson 4.4.3-201 - Bring missed 4.4 ARMv7 fixes from F-23 kernel - Fix deferred nouveau module loading on tegra diff --git a/pipe-limit-the-per-user-amount-of-pages-allocated-in.patch b/pipe-limit-the-per-user-amount-of-pages-allocated-in.patch new file mode 100644 index 0000000..7502c27 --- /dev/null +++ b/pipe-limit-the-per-user-amount-of-pages-allocated-in.patch @@ -0,0 +1,250 @@ +From 759c01142a5d0f364a462346168a56de28a80f52 Mon Sep 17 00:00:00 2001 +From: Willy Tarreau +Date: Mon, 18 Jan 2016 16:36:09 +0100 +Subject: [PATCH] pipe: limit the per-user amount of pages allocated in pipes + +On no-so-small systems, it is possible for a single process to cause an +OOM condition by filling large pipes with data that are never read. A +typical process filling 4000 pipes with 1 MB of data will use 4 GB of +memory. On small systems it may be tricky to set the pipe max size to +prevent this from happening. + +This patch makes it possible to enforce a per-user soft limit above +which new pipes will be limited to a single page, effectively limiting +them to 4 kB each, as well as a hard limit above which no new pipes may +be created for this user. This has the effect of protecting the system +against memory abuse without hurting other users, and still allowing +pipes to work correctly though with less data at once. + +The limit are controlled by two new sysctls : pipe-user-pages-soft, and +pipe-user-pages-hard. Both may be disabled by setting them to zero. The +default soft limit allows the default number of FDs per process (1024) +to create pipes of the default size (64kB), thus reaching a limit of 64MB +before starting to create only smaller pipes. With 256 processes limited +to 1024 FDs each, this results in 1024*64kB + (256*1024 - 1024) * 4kB = +1084 MB of memory allocated for a user. The hard limit is disabled by +default to avoid breaking existing applications that make intensive use +of pipes (eg: for splicing). + +Reported-by: socketpair@gmail.com +Reported-by: Tetsuo Handa +Mitigates: CVE-2013-4312 (Linux 2.0+) +Suggested-by: Linus Torvalds +Signed-off-by: Willy Tarreau +Signed-off-by: Al Viro +--- + Documentation/sysctl/fs.txt | 23 ++++++++++++++++++++++ + fs/pipe.c | 47 +++++++++++++++++++++++++++++++++++++++++++-- + include/linux/pipe_fs_i.h | 4 ++++ + include/linux/sched.h | 1 + + kernel/sysctl.c | 14 ++++++++++++++ + 5 files changed, 87 insertions(+), 2 deletions(-) + +diff --git a/Documentation/sysctl/fs.txt b/Documentation/sysctl/fs.txt +index 88152f214f48..302b5ed616a6 100644 +--- a/Documentation/sysctl/fs.txt ++++ b/Documentation/sysctl/fs.txt +@@ -32,6 +32,8 @@ Currently, these files are in /proc/sys/fs: + - nr_open + - overflowuid + - overflowgid ++- pipe-user-pages-hard ++- pipe-user-pages-soft + - protected_hardlinks + - protected_symlinks + - suid_dumpable +@@ -159,6 +161,27 @@ The default is 65534. + + ============================================================== + ++pipe-user-pages-hard: ++ ++Maximum total number of pages a non-privileged user may allocate for pipes. ++Once this limit is reached, no new pipes may be allocated until usage goes ++below the limit again. When set to 0, no limit is applied, which is the default ++setting. ++ ++============================================================== ++ ++pipe-user-pages-soft: ++ ++Maximum total number of pages a non-privileged user may allocate for pipes ++before the pipe size gets limited to a single page. Once this limit is reached, ++new pipes will be limited to a single page in size for this user in order to ++limit total memory usage, and trying to increase them using fcntl() will be ++denied until usage goes below the limit again. The default value allows to ++allocate up to 1024 pipes at their default size. When set to 0, no limit is ++applied. ++ ++============================================================== ++ + protected_hardlinks: + + A long-standing class of security issues is the hardlink-based +diff --git a/fs/pipe.c b/fs/pipe.c +index 42cf8ddf0e55..ab8dad3ccb6a 100644 +--- a/fs/pipe.c ++++ b/fs/pipe.c +@@ -38,6 +38,12 @@ unsigned int pipe_max_size = 1048576; + */ + unsigned int pipe_min_size = PAGE_SIZE; + ++/* Maximum allocatable pages per user. Hard limit is unset by default, soft ++ * matches default values. ++ */ ++unsigned long pipe_user_pages_hard; ++unsigned long pipe_user_pages_soft = PIPE_DEF_BUFFERS * INR_OPEN_CUR; ++ + /* + * We use a start+len construction, which provides full use of the + * allocated memory. +@@ -583,20 +589,49 @@ pipe_fasync(int fd, struct file *filp, int on) + return retval; + } + ++static void account_pipe_buffers(struct pipe_inode_info *pipe, ++ unsigned long old, unsigned long new) ++{ ++ atomic_long_add(new - old, &pipe->user->pipe_bufs); ++} ++ ++static bool too_many_pipe_buffers_soft(struct user_struct *user) ++{ ++ return pipe_user_pages_soft && ++ atomic_long_read(&user->pipe_bufs) >= pipe_user_pages_soft; ++} ++ ++static bool too_many_pipe_buffers_hard(struct user_struct *user) ++{ ++ return pipe_user_pages_hard && ++ atomic_long_read(&user->pipe_bufs) >= pipe_user_pages_hard; ++} ++ + struct pipe_inode_info *alloc_pipe_info(void) + { + struct pipe_inode_info *pipe; + + pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL); + if (pipe) { +- pipe->bufs = kzalloc(sizeof(struct pipe_buffer) * PIPE_DEF_BUFFERS, GFP_KERNEL); ++ unsigned long pipe_bufs = PIPE_DEF_BUFFERS; ++ struct user_struct *user = get_current_user(); ++ ++ if (!too_many_pipe_buffers_hard(user)) { ++ if (too_many_pipe_buffers_soft(user)) ++ pipe_bufs = 1; ++ pipe->bufs = kzalloc(sizeof(struct pipe_buffer) * pipe_bufs, GFP_KERNEL); ++ } ++ + if (pipe->bufs) { + init_waitqueue_head(&pipe->wait); + pipe->r_counter = pipe->w_counter = 1; +- pipe->buffers = PIPE_DEF_BUFFERS; ++ pipe->buffers = pipe_bufs; ++ pipe->user = user; ++ account_pipe_buffers(pipe, 0, pipe_bufs); + mutex_init(&pipe->mutex); + return pipe; + } ++ free_uid(user); + kfree(pipe); + } + +@@ -607,6 +642,8 @@ void free_pipe_info(struct pipe_inode_info *pipe) + { + int i; + ++ account_pipe_buffers(pipe, pipe->buffers, 0); ++ free_uid(pipe->user); + for (i = 0; i < pipe->buffers; i++) { + struct pipe_buffer *buf = pipe->bufs + i; + if (buf->ops) +@@ -998,6 +1035,7 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages) + memcpy(bufs + head, pipe->bufs, tail * sizeof(struct pipe_buffer)); + } + ++ account_pipe_buffers(pipe, pipe->buffers, nr_pages); + pipe->curbuf = 0; + kfree(pipe->bufs); + pipe->bufs = bufs; +@@ -1069,6 +1107,11 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) + if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) { + ret = -EPERM; + goto out; ++ } else if ((too_many_pipe_buffers_hard(pipe->user) || ++ too_many_pipe_buffers_soft(pipe->user)) && ++ !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) { ++ ret = -EPERM; ++ goto out; + } + ret = pipe_set_size(pipe, nr_pages); + break; +diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h +index eb8b8ac6df3c..24f5470d3944 100644 +--- a/include/linux/pipe_fs_i.h ++++ b/include/linux/pipe_fs_i.h +@@ -42,6 +42,7 @@ struct pipe_buffer { + * @fasync_readers: reader side fasync + * @fasync_writers: writer side fasync + * @bufs: the circular array of pipe buffers ++ * @user: the user who created this pipe + **/ + struct pipe_inode_info { + struct mutex mutex; +@@ -57,6 +58,7 @@ struct pipe_inode_info { + struct fasync_struct *fasync_readers; + struct fasync_struct *fasync_writers; + struct pipe_buffer *bufs; ++ struct user_struct *user; + }; + + /* +@@ -123,6 +125,8 @@ void pipe_unlock(struct pipe_inode_info *); + void pipe_double_lock(struct pipe_inode_info *, struct pipe_inode_info *); + + extern unsigned int pipe_max_size, pipe_min_size; ++extern unsigned long pipe_user_pages_hard; ++extern unsigned long pipe_user_pages_soft; + int pipe_proc_fn(struct ctl_table *, int, void __user *, size_t *, loff_t *); + + +diff --git a/include/linux/sched.h b/include/linux/sched.h +index 61aa9bbea871..1589ddc88e38 100644 +--- a/include/linux/sched.h ++++ b/include/linux/sched.h +@@ -835,6 +835,7 @@ struct user_struct { + #endif + unsigned long locked_shm; /* How many pages of mlocked shm ? */ + unsigned long unix_inflight; /* How many files in flight in unix sockets */ ++ atomic_long_t pipe_bufs; /* how many pages are allocated in pipe buffers */ + + #ifdef CONFIG_KEYS + struct key *uid_keyring; /* UID specific keyring */ +diff --git a/kernel/sysctl.c b/kernel/sysctl.c +index c810f8afdb7f..f6fd236429bd 100644 +--- a/kernel/sysctl.c ++++ b/kernel/sysctl.c +@@ -1757,6 +1757,20 @@ static struct ctl_table fs_table[] = { + .proc_handler = &pipe_proc_fn, + .extra1 = &pipe_min_size, + }, ++ { ++ .procname = "pipe-user-pages-hard", ++ .data = &pipe_user_pages_hard, ++ .maxlen = sizeof(pipe_user_pages_hard), ++ .mode = 0644, ++ .proc_handler = proc_doulongvec_minmax, ++ }, ++ { ++ .procname = "pipe-user-pages-soft", ++ .data = &pipe_user_pages_soft, ++ .maxlen = sizeof(pipe_user_pages_soft), ++ .mode = 0644, ++ .proc_handler = proc_doulongvec_minmax, ++ }, + { } + }; + +-- +2.5.0 +