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ANDROID: android-verity: Prevent double-freeing metadata

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If extract_metadata() fails, it will free metadata in its own error
path, so it is safe to simply return the provided error value without
worrying about resource handling/releasing.

Moreover, if we simply return in extract_metadata()'s error path, we
can assume the thread of execution will only make it down into the
free_metadata: tag area sometime after extract_metadata()'s success,
in which case metadata will need to be freed without question.

Bug: 234030265
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Change-Id: I1bf42ff9ecef3eea26543526c6955d7823d45c43
This commit is contained in:
Lee Jones
2022-06-07 15:28:37 +01:00
committed by Michael Bestas
parent edf1bf0833
commit 9e47d3f94d
1 changed files with 5 additions and 6 deletions
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7
drivers/md/dm-android-verity.c
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@@ -671,7 +671,7 @@ static int create_linear_device(struct dm_target *ti, dev_t dev,
static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv) static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
{ {
dev_t uninitialized_var(dev); dev_t uninitialized_var(dev);
struct android_metadata *metadata = NULL; struct android_metadata *metadata;
int err = 0, i, mode; int err = 0, i, mode;
char *key_id = NULL, *table_ptr, dummy, *target_device; char *key_id = NULL, *table_ptr, dummy, *target_device;
char *verity_table_args[VERITY_TABLE_ARGS + 2 + VERITY_TABLE_OPT_FEC_ARGS]; char *verity_table_args[VERITY_TABLE_ARGS + 2 + VERITY_TABLE_OPT_FEC_ARGS];
@@ -733,7 +733,7 @@ static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
} }
DMERR("Error while extracting metadata"); DMERR("Error while extracting metadata");
handle_error(); handle_error();
goto free_metadata; return err;
} }
if (verity_enabled) { if (verity_enabled) {
@@ -864,11 +864,10 @@ static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
} }
free_metadata: free_metadata:
if (metadata) {
kfree(metadata->header); kfree(metadata->header);
kfree(metadata->verity_table); kfree(metadata->verity_table);
}
kfree(metadata); kfree(metadata);
return err; return err;
} }