Re: [RFC PATCH] mm/mempolicy: Fix memory leak in set_mempolicy_home_node system call
From: Huang, Ying <hidden>
Date: 2022-12-15 06:35:26
Also in:
lkml, stable
Mathieu Desnoyers [off-list ref] writes:
When encountering any vma in the range with policy other than MPOL_BIND
or MPOL_PREFERRED_MANY, an error is returned without issuing a mpol_put
on the policy just allocated with mpol_dup().
This allows arbitrary users to leak kernel memory.
Fixes: c6018b4b2549 ("mm/mempolicy: add set_mempolicy_home_node syscall")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Aneesh Kumar K.V <redacted>
Cc: Ben Widawsky <redacted>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Feng Tang <redacted>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andrea Arcangeli <redacted>
Cc: Mel Gorman <redacted>
Cc: Mike Kravetz <redacted>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <redacted>
Cc: Andi Kleen <redacted>
Cc: Dan Williams <redacted>
Cc: Huang Ying <redacted>
Cc: <redacted>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org # 5.17+Reviewed-by: "Huang, Ying" <redacted> Thanks!
quoted hunk
--- mm/mempolicy.c | 1 + 1 file changed, 1 insertion(+)diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 61aa9aedb728..02c8a712282f 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c@@ -1540,6 +1540,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le * the home node for vmas we already updated before. */ if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) { + mpol_put(new); err = -EOPNOTSUPP; break; }