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authorRenaud Lottiaux <renaud.lottiaux@kerlabs.com>2009-06-30 14:41:34 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-30 21:56:00 -0400
commitdf279ca8966c3de83105428e3391ab17690802a9 (patch)
tree9c10bbad25bbb8f3b40bd25ec3aadf8f0c0a4324 /kernel/acct.c
parentb4f90189dc2c7a7e6926ea480ae3404ec3de4581 (diff)
bsdacct: fix access to invalid filp in acct_on()
The file opened in acct_on and freshly stored in the ns->bacct struct can be closed in acct_file_reopen by a concurrent call after we release acct_lock and before we call mntput(file->f_path.mnt). Record file->f_path.mnt in a local variable and use this variable only. Signed-off-by: Renaud Lottiaux <renaud.lottiaux@kerlabs.com> Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/acct.c')
-rw-r--r--kernel/acct.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/acct.c b/kernel/acct.c
index 7afa31564162..9f3391090b3e 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -215,6 +215,7 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,
215static int acct_on(char *name) 215static int acct_on(char *name)
216{ 216{
217 struct file *file; 217 struct file *file;
218 struct vfsmount *mnt;
218 int error; 219 int error;
219 struct pid_namespace *ns; 220 struct pid_namespace *ns;
220 struct bsd_acct_struct *acct = NULL; 221 struct bsd_acct_struct *acct = NULL;
@@ -256,11 +257,12 @@ static int acct_on(char *name)
256 acct = NULL; 257 acct = NULL;
257 } 258 }
258 259
259 mnt_pin(file->f_path.mnt); 260 mnt = file->f_path.mnt;
261 mnt_pin(mnt);
260 acct_file_reopen(ns->bacct, file, ns); 262 acct_file_reopen(ns->bacct, file, ns);
261 spin_unlock(&acct_lock); 263 spin_unlock(&acct_lock);
262 264
263 mntput(file->f_path.mnt); /* it's pinned, now give up active reference */ 265 mntput(mnt); /* it's pinned, now give up active reference */
264 kfree(acct); 266 kfree(acct);
265 267
266 return 0; 268 return 0;