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authorKees Cook <keescook@chromium.org>2017-05-16 12:03:31 -0700
committerKees Cook <keescook@chromium.org>2017-05-31 10:13:42 -0700
commit656de42e83379e5348e3f4236ff1d79353edfb28 (patch)
tree08af3b75f5c4b4a6e725d19ce45d3455c9081286 /fs/pstore
parentf6525b96dd9f68efe374e5aef864975e628de991 (diff)
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pstore: Avoid potential infinite loop
If a backend does not correctly iterate through its records, pstore will get stuck loading entries. Detect this with a large record count, and announce if we ever hit the limit. This will let future backend reading bugs less annoying to debug. Additionally adjust the error about pstore_mkfile() failing. Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'fs/pstore')
-rw-r--r--fs/pstore/platform.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 4c5cd9368460..d8289ce00f99 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -822,6 +822,7 @@ void pstore_get_backend_records(struct pstore_info *psi,
struct dentry *root, int quiet)
{
int failed = 0;
+ unsigned int stop_loop = 65536;
if (!psi || !root)
return;
@@ -835,7 +836,7 @@ void pstore_get_backend_records(struct pstore_info *psi,
* may reallocate record.buf. On success, pstore_mkfile() will keep
* the record.buf, so free it only on failure.
*/
- for (;;) {
+ for (; stop_loop; stop_loop--) {
struct pstore_record *record;
int rc;
@@ -870,8 +871,11 @@ out:
mutex_unlock(&psi->read_mutex);
if (failed)
- pr_warn("failed to load %d record(s) from '%s'\n",
+ pr_warn("failed to create %d record(s) from '%s'\n",
failed, psi->name);
+ if (!stop_loop)
+ pr_err("looping? Too many records seen from '%s'\n",
+ psi->name);
}
static void pstore_dowork(struct work_struct *work)