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author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2015-01-08 18:51:47 +0100 |
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committer | Matt Fleming <matt.fleming@intel.com> | 2015-01-20 23:13:33 +0100 |
commit | d1a8d66b9177105e898e73716f97eb61842c457a (patch) | |
tree | 743fa621077ce787e58a98d0b9a9b803df25f2b3 /drivers/firmware | |
parent | efi: Small leak on error in runtime map code (diff) | |
download | linux-d1a8d66b9177105e898e73716f97eb61842c457a.tar.xz linux-d1a8d66b9177105e898e73716f97eb61842c457a.zip |
efi/libstub: Call get_memory_map() to obtain map and desc sizes
This fixes two minor issues in the implementation of get_memory_map():
- Currently, it assumes that sizeof(efi_memory_desc_t) == desc_size,
which is usually true, but not mandated by the spec. (This was added
intentionally to allow future additions to the definition of
efi_memory_desc_t). The way the loop is implemented currently, the
added slack space may be insufficient if desc_size is larger, which in
some corner cases could result in the loop never terminating.
- It allocates 32 efi_memory_desc_t entries first (again, using the size
of the struct instead of desc_size), and frees and reallocates if it
turns out to be insufficient. Few implementations of UEFI have such small
memory maps, which results in a unnecessary allocate/free pair on each
invocation.
Fix this by calling the get_memory_map() boot service first with a '0'
input value for map size to retrieve the map size and desc size from the
firmware and only then perform the allocation, using desc_size rather
than sizeof(efi_memory_desc_t).
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Diffstat (limited to 'drivers/firmware')
-rw-r--r-- | drivers/firmware/efi/libstub/efi-stub-helper.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index 9bd9fbb5bea8..d073e3946383 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -66,25 +66,29 @@ efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg, unsigned long key; u32 desc_version; - *map_size = sizeof(*m) * 32; -again: + *map_size = 0; + *desc_size = 0; + key = 0; + status = efi_call_early(get_memory_map, map_size, NULL, + &key, desc_size, &desc_version); + if (status != EFI_BUFFER_TOO_SMALL) + return EFI_LOAD_ERROR; + /* * Add an additional efi_memory_desc_t because we're doing an * allocation which may be in a new descriptor region. */ - *map_size += sizeof(*m); + *map_size += *desc_size; status = efi_call_early(allocate_pool, EFI_LOADER_DATA, *map_size, (void **)&m); if (status != EFI_SUCCESS) goto fail; - *desc_size = 0; - key = 0; status = efi_call_early(get_memory_map, map_size, m, &key, desc_size, &desc_version); if (status == EFI_BUFFER_TOO_SMALL) { efi_call_early(free_pool, m); - goto again; + return EFI_LOAD_ERROR; } if (status != EFI_SUCCESS) |