From: Yisheng Xie xieyisheng1@huawei.com
[ Upstream commit 56521e7a02b7b84a5e72691a1fb15570e6055545 ]
As Xiaojun reported the ltp of migrate_pages01 will fail on arm64 system which has 4 nodes[0...3], all have memory and CONFIG_NODES_SHIFT=2:
migrate_pages01 0 TINFO : test_invalid_nodes migrate_pages01 14 TFAIL : migrate_pages_common.c:45: unexpected failure - returned value = 0, expected: -1 migrate_pages01 15 TFAIL : migrate_pages_common.c:55: call succeeded unexpectedly
In this case the test_invalid_nodes of migrate_pages01 will call: SYSC_migrate_pages as:
migrate_pages(0, , {0x0000000000000001}, 64, , {0x0000000000000010}, 64) = 0
The new nodes specifies one or more node IDs that are greater than the maximum supported node ID, however, the errno is not set to EINVAL as expected.
As man pages of set_mempolicy[1], mbind[2], and migrate_pages[3] mentioned, when nodemask specifies one or more node IDs that are greater than the maximum supported node ID, the errno should set to EINVAL. However, get_nodes only check whether the part of bits [BITS_PER_LONG*BITS_TO_LONGS(MAX_NUMNODES), maxnode) is zero or not, and remain [MAX_NUMNODES, BITS_PER_LONG*BITS_TO_LONGS(MAX_NUMNODES) unchecked.
This patch is to check the bits of [MAX_NUMNODES, maxnode) in get_nodes to let migrate_pages set the errno to EINVAL when nodemask specifies one or more node IDs that are greater than the maximum supported node ID, which follows the manpage's guide.
[1] http://man7.org/linux/man-pages/man2/set_mempolicy.2.html [2] http://man7.org/linux/man-pages/man2/mbind.2.html [3] http://man7.org/linux/man-pages/man2/migrate_pages.2.html
Link: http://lkml.kernel.org/r/1510882624-44342-3-git-send-email-xieyisheng1@huawe... Signed-off-by: Yisheng Xie xieyisheng1@huawei.com Reported-by: Tan Xiaojun tanxiaojun@huawei.com Acked-by: Vlastimil Babka vbabka@suse.cz Cc: Andi Kleen ak@linux.intel.com Cc: Chris Salls salls@cs.ucsb.edu Cc: Christopher Lameter cl@linux.com Cc: David Rientjes rientjes@google.com Cc: Ingo Molnar mingo@kernel.org Cc: Naoya Horiguchi n-horiguchi@ah.jp.nec.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- mm/mempolicy.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index d326955b4d05..3cd93e8c9c43 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1286,6 +1286,7 @@ static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask, unsigned long maxnode) { unsigned long k; + unsigned long t; unsigned long nlongs; unsigned long endmask;
@@ -1302,13 +1303,19 @@ static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask, else endmask = (1UL << (maxnode % BITS_PER_LONG)) - 1;
- /* When the user specified more nodes than supported just check - if the non supported part is all zero. */ + /* + * When the user specified more nodes than supported just check + * if the non supported part is all zero. + * + * If maxnode have more longs than MAX_NUMNODES, check + * the bits in that area first. And then go through to + * check the rest bits which equal or bigger than MAX_NUMNODES. + * Otherwise, just check bits [MAX_NUMNODES, maxnode). + */ if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) { if (nlongs > PAGE_SIZE/sizeof(long)) return -EINVAL; for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) { - unsigned long t; if (get_user(t, nmask + k)) return -EFAULT; if (k == nlongs - 1) { @@ -1321,6 +1328,16 @@ static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask, endmask = ~0UL; }
+ if (maxnode > MAX_NUMNODES && MAX_NUMNODES % BITS_PER_LONG != 0) { + unsigned long valid_mask = endmask; + + valid_mask &= ~((1UL << (MAX_NUMNODES % BITS_PER_LONG)) - 1); + if (get_user(t, nmask + nlongs - 1)) + return -EFAULT; + if (t & valid_mask) + return -EINVAL; + } + if (copy_from_user(nodes_addr(*nodes), nmask, nlongs*sizeof(unsigned long))) return -EFAULT; nodes_addr(*nodes)[nlongs-1] &= endmask;