[PATCH] virDevMapperGetTargetsImpl: Use correct length when copying into dm.name

8 Mar 2021

For reasons unknown, when rewriting this code and dropping
libdevmapper I've mistakenly used incorrect length of dm.name. In
linux/dm-ioctl.h the dm_ioctl struct is defined as follows:

  #define DM_NAME_LEN 128

  struct dm_ioctl {
    ...
    char name[DM_NAME_LEN];     /* device name */
    ...
  };

However, when copying string into this member, DM_TABLE_DEPS was
used, which is defined as follows:

  #define DM_TABLE_DEPS    _IOWR(DM_IOCTL, DM_TABLE_DEPS_CMD, struct dm_ioctl)

After decryption, this results in the following size: 3241737483.

Fixes: 22494556542c676d1b9e7f1c1f2ea13ac17e1e3e
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/util/virdevmapper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/util/virdevmapper.c b/src/util/virdevmapper.c
index fcb11e954f..2c4c2df999 100644
--- a/src/util/virdevmapper.c
+++ b/src/util/virdevmapper.c
@@ -240,7 +240,7 @@ virDevMapperGetTargetsImpl(int controlFD,
     if (!(sanitizedPath = virDMSanitizepath(path)))
         return 0;
 
-    if (virStrcpy(dm.name, sanitizedPath, DM_TABLE_DEPS) < 0) {
+    if (virStrcpy(dm.name, sanitizedPath, DM_NAME_LEN) < 0) {
         virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
                        _("Resolved device mapper name too long"));
         return -1;
-- 
2.26.2

    

Michal Privoznik

Daniel P. Berrangé

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