Messages in this thread | | | Date | Thu, 2 Aug 2018 00:06:09 -0400 | From | "Theodore Y. Ts'o" <> | Subject | Re: [PATCH v2] ext4: mballoc: Fix spectre gadget in ext4_mb_regular_allocator |
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On Mon, Jul 30, 2018 at 06:07:47PM +0000, Jeremy Cline wrote: > 'ac->ac_g_ex.fe_len' is a user-controlled value which is used in the > derivation of 'ac->ac_2order'. 'ac->ac_2order', in turn, is used to > index arrays which makes it a potential spectre gadget. Fix this by > sanitizing the value assigned to 'ac->ac2_order'. This covers the > following accesses found with the help of smatch: > > * fs/ext4/mballoc.c:1896 ext4_mb_simple_scan_group() warn: potential > spectre issue 'grp->bb_counters' [w] (local cap) > > * fs/ext4/mballoc.c:445 mb_find_buddy() warn: potential spectre issue > 'EXT4_SB(e4b->bd_sb)->s_mb_offsets' [r] (local cap) > > * fs/ext4/mballoc.c:446 mb_find_buddy() warn: potential spectre issue > 'EXT4_SB(e4b->bd_sb)->s_mb_maxs' [r] (local cap) > > Cc: Josh Poimboeuf <jpoimboe@redhat.com> > Cc: stable@vger.kernel.org > Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> > Signed-off-by: Jeremy Cline <jcline@redhat.com>
Thanks, applied.
- Ted
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