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From: Prasad J Pandit <pjp@fedoraproject.org>
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Date: Mon, 16 Oct 2017 14:21:59 +0200
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Subject: [PATCH] 9pfs: use g_malloc0 to allocate space for xattr
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9p back-end first queries the size of an extended attribute,
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allocates space for it via g_malloc() and then retrieves its
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value into allocated buffer. Race between querying attribute
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size and retrieving its could lead to memory bytes disclosure.
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Use g_malloc0() to avoid it.
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Reported-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
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Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
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Signed-off-by: Greg Kurz <groug@kaod.org>
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(cherry picked from commit 7bd92756303f2158a68d5166264dc30139b813b6)
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---
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 hw/9pfs/9p.c | 4 ++--
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 1 file changed, 2 insertions(+), 2 deletions(-)
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diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
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index 8e9490c5f5..c41c0eb106 100644
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--- a/hw/9pfs/9p.c
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+++ b/hw/9pfs/9p.c
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@@ -3236,7 +3236,7 @@ static void coroutine_fn v9fs_xattrwalk(void *opaque)
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         xattr_fidp->fid_type = P9_FID_XATTR;
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         xattr_fidp->fs.xattr.xattrwalk_fid = true;
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         if (size) {
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-            xattr_fidp->fs.xattr.value = g_malloc(size);
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+            xattr_fidp->fs.xattr.value = g_malloc0(size);
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             err = v9fs_co_llistxattr(pdu, &xattr_fidp->path,
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                                      xattr_fidp->fs.xattr.value,
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                                      xattr_fidp->fs.xattr.len);
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@@ -3269,7 +3269,7 @@ static void coroutine_fn v9fs_xattrwalk(void *opaque)
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         xattr_fidp->fid_type = P9_FID_XATTR;
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         xattr_fidp->fs.xattr.xattrwalk_fid = true;
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         if (size) {
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-            xattr_fidp->fs.xattr.value = g_malloc(size);
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+            xattr_fidp->fs.xattr.value = g_malloc0(size);
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             err = v9fs_co_lgetxattr(pdu, &xattr_fidp->path,
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                                     &name, xattr_fidp->fs.xattr.value,
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                                     xattr_fidp->fs.xattr.len);