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authorLin Feng <linf@wangsu.com>2021-02-25 17:20:53 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-26 09:41:03 -0800
commit3b3376f222e3ab58367d9dd405cafd09d5e37b7c (patch)
treedbe1cb937b2b318e6460f484fcb203a8344f9426 /kernel
parent4508943794efdd94171549c0bd52810e2f4ad9fe (diff)
downloadlinux-3b3376f222e3ab58367d9dd405cafd09d5e37b7c.tar.gz
sysctl.c: fix underflow value setting risk in vm_table
Apart from subsystem specific .proc_handler handler, all ctl_tables with extra1 and extra2 members set should use proc_dointvec_minmax instead of proc_dointvec, or the limit set in extra* never work and potentially echo underflow values(negative numbers) is likely make system unstable. Especially vfs_cache_pressure and zone_reclaim_mode, -1 is apparently not a valid value, but we can set to them. And then kernel may crash. # echo -1 > /proc/sys/vm/vfs_cache_pressure Link: https://lkml.kernel.org/r/20201223105535.2875-1-linf@wangsu.com Signed-off-by: Lin Feng <linf@wangsu.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sysctl.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c9fbdd848138..62fbd09b5dc1 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2962,7 +2962,7 @@ static struct ctl_table vm_table[] = {
.data = &block_dump,
.maxlen = sizeof(block_dump),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
{
@@ -2970,7 +2970,7 @@ static struct ctl_table vm_table[] = {
.data = &sysctl_vfs_cache_pressure,
.maxlen = sizeof(sysctl_vfs_cache_pressure),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
@@ -2980,7 +2980,7 @@ static struct ctl_table vm_table[] = {
.data = &sysctl_legacy_va_layout,
.maxlen = sizeof(sysctl_legacy_va_layout),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
#endif
@@ -2990,7 +2990,7 @@ static struct ctl_table vm_table[] = {
.data = &node_reclaim_mode,
.maxlen = sizeof(node_reclaim_mode),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
},
{