The patch titled
Subject: kernel/sysctl.c: ignore out-of-range taint bits introduced via kernel.tainted
has been added to the -mm tree. Its filename is
kernel-sysctl-ignore-out-of-range-taint-bits-introduced-via-kerneltainted.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kernel-sysctl-ignore-out-of-range-taint-bits-introduced-via-kerneltainted.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kernel-sysctl-ignore-out-of-range-taint-bits-introduced-via-kerneltainted.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Rafael Aquini <aquini@xxxxxxxxxx>
Subject: kernel/sysctl.c: ignore out-of-range taint bits introduced via kernel.tainted
Users with SYS_ADMIN capability can add arbitrary taint flags to the
running kernel by writing to /proc/sys/kernel/tainted or issuing the
command 'sysctl -w kernel.tainted=...'. This interface, however, is open
for any integer value and this might cause an invalid set of flags being
committed to the tainted_mask bitset.
This patch introduces a simple way for proc_taint() to ignore any eventual
invalid bit coming from the user input before committing those bits to the
kernel tainted_mask.
Link: http://lkml.kernel.org/r/20200512223946.888020-1-aquini@xxxxxxxxxx
Signed-off-by: Rafael Aquini <aquini@xxxxxxxxxx>
Reviewed-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Iurii Zaikin <yzaikin@xxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/sysctl.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/kernel/sysctl.c~kernel-sysctl-ignore-out-of-range-taint-bits-introduced-via-kerneltainted
+++ a/kernel/sysctl.c
@@ -870,10 +870,9 @@ static int proc_taint(struct ctl_table *
* to everyone's atomic.h for this
*/
int i;
- for (i = 0; i < BITS_PER_LONG && tmptaint >> i; i++) {
- if ((tmptaint >> i) & 1)
+ for (i = 0; i < TAINT_FLAGS_COUNT; i++)
+ if ((1UL << i) & tmptaint)
add_taint(i, LOCKDEP_STILL_OK);
- }
}
return err;
_
Patches currently in -mm which might be from aquini@xxxxxxxxxx are
mm-slub-add-panic_on_error-to-the-debug-facilities.patch
kernel-sysctl-ignore-out-of-range-taint-bits-introduced-via-kerneltainted.patch
