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Commit c4d0c3b097f7584772316ee4d64a09fe0e4ddfca

Authored by Dan Rosenberg
Committed by Alex Elder
1 parent 9681153b46
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

xfs: prevent leaking uninitialized stack memory in FSGEOMETRY_V1 

The FSGEOMETRY_V1 ioctl (and its compat equivalent) calls out to
xfs_fs_geometry() with a version number of 3.  This code path does not
fill in the logsunit member of the passed xfs_fsop_geom_t, leading to
the leaking of four bytes of uninitialized stack data to potentially
unprivileged callers.

v2 switches to memset() to avoid future issues if structure members
change, on suggestion of Dave Chinner.

Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Reviewed-by: Eugene Teo <eugeneteo@kernel.org>
Signed-off-by: Alex Elder <aelder@sgi.com>

Showing 1 changed file with 3 additions and 0 deletions Side-by-side Diff

... ... @@ -53,6 +53,9 @@
53 53 xfs_fsop_geom_t *geo,
54 54 int new_version)
55 55 {
  56 +
  57 + memset(geo, 0, sizeof(*geo));
  58 +
56 59 geo->blocksize = mp->m_sb.sb_blocksize;
57 60 geo->rtextsize = mp->m_sb.sb_rextsize;
58 61 geo->agblocks = mp->m_sb.sb_agblocks;