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| author | Randy Dunlap <rdunlap@infradead.org> | 2020-04-02 07:10:58 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-02 19:35:32 +0300 |
| commit | aa9f7d5172fac9bf1f09e678c35e287a40a7b7dd (patch) | |
| tree | 68c1de97cf7b4653313a39427c5ad63a05f9dacc | |
| parent | d888fb2b189be07df1656a31930b11a62ae88e58 (diff) | |
| download | linux-aa9f7d5172fac9bf1f09e678c35e287a40a7b7dd.tar.xz | |
mm: mempolicy: require at least one nodeid for MPOL_PREFERRED
Using an empty (malformed) nodelist that is not caught during mount option
parsing leads to a stack-out-of-bounds access.
The option string that was used was: "mpol=prefer:,". However,
MPOL_PREFERRED requires a single node number, which is not being provided
here.
Add a check that 'nodes' is not empty after parsing for MPOL_PREFERRED's
nodeid.
Fixes: 095f1fc4ebf3 ("mempolicy: rework shmem mpol parsing and display")
Reported-by: Entropy Moe <3ntr0py1337@gmail.com>
Reported-by: syzbot+b055b1a6b2b958707a21@syzkaller.appspotmail.com
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: syzbot+b055b1a6b2b958707a21@syzkaller.appspotmail.com
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Link: http://lkml.kernel.org/r/89526377-7eb6-b662-e1d8-4430928abde9@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/mempolicy.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 460683bbe58c..5fb427aed612 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2898,7 +2898,9 @@ int mpol_parse_str(char *str, struct mempolicy **mpol) switch (mode) { case MPOL_PREFERRED: /* - * Insist on a nodelist of one node only + * Insist on a nodelist of one node only, although later + * we use first_node(nodes) to grab a single node, so here + * nodelist (or nodes) cannot be empty. */ if (nodelist) { char *rest = nodelist; @@ -2906,6 +2908,8 @@ int mpol_parse_str(char *str, struct mempolicy **mpol) rest++; if (*rest) goto out; + if (nodes_empty(nodes)) + goto out; } break; case MPOL_INTERLEAVE: |