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disk: efi: Fix memory leak on 'gpt guid'

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Below is what happens on R-Car H3ULCB-KF using clean U-Boot
v2019.04-00810-g6aebc0d11a10 and r8a7795_ulcb_defconfig:

 => ### interrupt autoboot
 => gpt guid mmc 1
 21200400-0804-0146-9dcc-a8c51255994f
 success!
 => ### keep calling 'gpt guid mmc 1'
 => ### on 59th call, we are out of memory:
 => gpt guid mmc 1
 alloc_read_gpt_entries: ERROR: Can't allocate 0X4000 bytes for GPT Entries
 GPT: Failed to allocate memory for PTE
 get_disk_guid: *** ERROR: Invalid GPT ***
 alloc_read_gpt_entries: ERROR: Can't allocate 0X4000 bytes for GPT Entries
 GPT: Failed to allocate memory for PTE
 get_disk_guid: *** ERROR: Invalid Backup GPT ***
 error!

After some inspection, it looks like get_disk_guid(), added via v2017.09
commit 73d6d18b71 ("GPT: add accessor function for disk GUID"),
unlike other callers of is_gpt_valid(), doesn't free the memory pointed
out by 'gpt_entry *gpt_pte'. The latter is allocated by is_gpt_valid()
via alloc_read_gpt_entries().

With the fix applied, the reproduction scenario has been run hundreds
of times ('while true; do gpt guid mmc 1; done') w/o running into OOM.

Fixes: 73d6d18b71 ("GPT: add accessor function for disk GUID")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Eugeniu Rosca 2019-04-30 04:53:44 +02:00 committed by Heinrich Schuchardt
parent e6023be41e
commit 1cfe969475
1 changed files with 2 additions and 0 deletions
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2
disk/part_efi.c
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@ -209,6 +209,8 @@ int get_disk_guid(struct blk_desc * dev_desc, char *guid)
guid_bin = gpt_head->disk_guid.b;
uuid_bin_to_str(guid_bin, guid, UUID_STR_FORMAT_GUID);
/* Remember to free pte */
free(gpt_pte);
return 0;
}