[PATCHv2] cmd/gpt: Address error cases during gpt rename more correctly
Tom Rini
trini at konsulko.com
Tue Jan 21 17:41:04 CET 2020
On Tue, Jan 21, 2020 at 08:33:04AM +0100, Simon Goldschmidt wrote:
> On Mon, Jan 20, 2020 at 11:53 PM Tom Rini <trini at konsulko.com> wrote:
> >
> > New analysis by the tool has shown that we have some cases where we
> > weren't handling the error exit condition correctly. When we ran into
> > the ENOMEM case we wouldn't exit the function and thus incorrect things
> > could happen. Rework the unwinding such that we don't need a helper
> > function now and free what we may have allocated.
> >
> > Fixes: 18030d04d25d ("GPT: fix memory leaks identified by Coverity")
> > Reported-by: Coverity (CID: 275475, 275476)
> > Cc: Alison Chaiken <alison at she-devel.com>
> > Cc: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>
> > Cc: Jordy <jordy at simplyhacker.com>
> > Signed-off-by: Tom Rini <trini at konsulko.com>
> >
> > ---
> > Changes in v2:
> > - Initialize str_disk_guid to NULL to be sure we can test that it has
> > been set later on (Simon, Jordy).
> >
> > cmd/gpt.c | 37 +++++++++----------------------------
> > 1 file changed, 9 insertions(+), 28 deletions(-)
> >
> > diff --git a/cmd/gpt.c b/cmd/gpt.c
> > index 0c4349f4b249..c0e3c5161789 100644
> > --- a/cmd/gpt.c
> > +++ b/cmd/gpt.c
> > @@ -633,21 +633,6 @@ static int do_disk_guid(struct blk_desc *dev_desc, char * const namestr)
> > }
> >
> > #ifdef CONFIG_CMD_GPT_RENAME
> > -/*
> > - * There are 3 malloc() calls in set_gpt_info() and there is no info about which
> > - * failed.
> > - */
> > -static void set_gpt_cleanup(char **str_disk_guid,
> > - disk_partition_t **partitions)
> > -{
> > -#ifdef CONFIG_RANDOM_UUID
> > - if (str_disk_guid)
> > - free(str_disk_guid);
> > -#endif
> > - if (partitions)
> > - free(partitions);
> > -}
> > -
> > static int do_rename_gpt_parts(struct blk_desc *dev_desc, char *subcomm,
> > char *name1, char *name2)
> > {
> > @@ -655,7 +640,7 @@ static int do_rename_gpt_parts(struct blk_desc *dev_desc, char *subcomm,
> > struct disk_part *curr;
> > disk_partition_t *new_partitions = NULL;
> > char disk_guid[UUID_STR_LEN + 1];
> > - char *partitions_list, *str_disk_guid;
> > + char *partitions_list, *str_disk_guid = NULL;
> > u8 part_count = 0;
> > int partlistlen, ret, numparts = 0, partnum, i = 1, ctr1 = 0, ctr2 = 0;
> >
> > @@ -699,11 +684,7 @@ static int do_rename_gpt_parts(struct blk_desc *dev_desc, char *subcomm,
> > &new_partitions, &part_count);
> > if (ret < 0) {
> > del_gpt_info();
> > - free(partitions_list);
> > - if (ret == -ENOMEM)
> > - set_gpt_cleanup(&str_disk_guid, &new_partitions);
> > - else
> > - goto out;
> > + goto out;
> > }
> >
> > if (!strcmp(subcomm, "swap")) {
> > @@ -768,11 +749,7 @@ static int do_rename_gpt_parts(struct blk_desc *dev_desc, char *subcomm,
> > */
> > if (ret < 0) {
> > del_gpt_info();
> > - free(partitions_list);
> > - if (ret == -ENOMEM)
> > - set_gpt_cleanup(&str_disk_guid, &new_partitions);
> > - else
> > - goto out;
> > + goto out;
> > }
> >
> > debug("Writing new partition table\n");
> > @@ -797,8 +774,12 @@ static int do_rename_gpt_parts(struct blk_desc *dev_desc, char *subcomm,
> > print_gpt_info();
> > del_gpt_info();
> > out:
>
> OK, so the freeing below looks good to me now. However, what worries me is that
> when reaching 'out:' via different code flows, del_gpt_info is not always
> called. I think that could lead to memory leaks when calling this code again, as
> get_gpt_info just reinitializes the list head without checking if there's
> actually something allocated in the list.
>
> Maybe we should move the last call to del_gpt_info below 'out:' so that it is
> always called?
I think that's safe to do, yes. v3 coming up..
--
Tom
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