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cbfs: Add unverified_area APIs

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This patch adds a new ..._unverified_area_... group of functions to the
cbfs_map/_load/_alloc() APIs. These functions can be used to access
custom FMAP sections and are meant to replace the existing
cbfs_locate_file_in_region(). The name is intended to highlight that
accesses through this API will not be verified when CBFS_VERIFICATION is
enabled and should always be treated as if they may return malicious
data. (Due to laziness I'm not adding the combination of this API with
the ..._type_... variant at this point, since it seems very unlikely
that we'll ever have a use case for that. If we ever do, it should be
easy to add later.)

(Also remove the 'inline' from cbfs_file_hash_mismatch(). I'm not sure
why I put it there in the first place, probably a bad copy&paste.)

Signed-off-by: Julius Werner <jwerner@chromium.org>
Change-Id: I402265900f7075aa0c2f58d812c67ea63ddf2900
Reviewed-on: https://review.coreboot.org/c/coreboot/+/59678
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
This commit is contained in:
Julius Werner 2021-04-15 23:25:44 -07:00
commit 05714ccab7
2 changed files with 147 additions and 74 deletions
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47
src/include/cbfs.h
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@ -55,6 +55,11 @@
* section), even when running in an RW stage from one of the RW CBFSs. Only relevant if
* CONFIG(VBOOT) is set.
*
* ..._unverified_area_...: Will look for the CBFS file in the named FMAP area, rather than
* any of the default (RO or RW) CBFSs. Files accessed this way are *not* verified in any
* way (even if CONFIG(CBFS_VERIFICATION) is enabled) and should always be treated as
* untrusted (potentially malicious) data. Mutually exclusive with the ..._ro_... variant.
*
* ..._type_...: May pass in an extra enum cbfs_type *type parameter. If the value it points to
* is CBFS_TYPE_QUERY, it will be replaced with the actual CBFS type of the found file. If
* it is anything else, the type will be compared with the actually found type, and the
@ -76,11 +81,15 @@ static inline size_t cbfs_type_load(const char *name, void *buf, size_t size,
enum cbfs_type *type);
static inline size_t cbfs_ro_type_load(const char *name, void *buf, size_t size,
enum cbfs_type *type);
static inline size_t cbfs_unverified_area_load(const char *area, const char *name,
void *buf, size_t size);
static inline void *cbfs_map(const char *name, size_t *size_out);
static inline void *cbfs_ro_map(const char *name, size_t *size_out);
static inline void *cbfs_type_map(const char *name, size_t *size_out, enum cbfs_type *type);
static inline void *cbfs_ro_type_map(const char *name, size_t *size_out, enum cbfs_type *type);
static inline void *cbfs_unverified_area_map(const char *area, const char *name,
size_t *size_out);
static inline void *cbfs_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
size_t *size_out);
@ -90,6 +99,9 @@ static inline void *cbfs_type_alloc(const char *name, cbfs_allocator_t allocator
size_t *size_out, enum cbfs_type *type);
static inline void *cbfs_ro_type_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
size_t *size_out, enum cbfs_type *type);
static inline void *cbfs_unverified_area_alloc(const char *area, const char *name,
cbfs_allocator_t allocator, void *arg,
size_t *size_out);
static inline void *cbfs_cbmem_alloc(const char *name, uint32_t cbmem_id, size_t *size_out);
static inline void *cbfs_ro_cbmem_alloc(const char *name, uint32_t cbmem_id, size_t *size_out);
@ -97,6 +109,8 @@ static inline void *cbfs_type_cbmem_alloc(const char *name, uint32_t cbmem_id, s
enum cbfs_type *type);
static inline void *cbfs_ro_type_cbmem_alloc(const char *name, uint32_t cbmem_id,
size_t *size_out, enum cbfs_type *type);
static inline void *cbfs_unverified_area_cbmem_alloc(const char *area, const char *name,
uint32_t cbmem_id, size_t *size_out);
/*
* Starts the processes of preloading a file into RAM.
@ -194,6 +208,9 @@ cb_err_t _cbfs_boot_lookup(const char *name, bool force_ro,
void *_cbfs_alloc(const char *name, cbfs_allocator_t allocator, void *arg,
size_t *size_out, bool force_ro, enum cbfs_type *type);
void *_cbfs_unverified_area_alloc(const char *area, const char *name,
cbfs_allocator_t allocator, void *arg, size_t *size_out);
struct _cbfs_default_allocator_arg {
void *buf;
size_t buf_size;
@ -229,6 +246,13 @@ static inline void *cbfs_ro_type_alloc(const char *name, cbfs_allocator_t alloca
return _cbfs_alloc(name, allocator, arg, size_out, true, type);
}
static inline void *cbfs_unverified_area_alloc(const char *area, const char *name,
cbfs_allocator_t allocator, void *arg,
size_t *size_out)
{
return _cbfs_unverified_area_alloc(area, name, allocator, arg, size_out);
}
static inline void *cbfs_map(const char *name, size_t *size_out)
{
return cbfs_type_map(name, size_out, NULL);
@ -249,6 +273,12 @@ static inline void *cbfs_ro_type_map(const char *name, size_t *size_out, enum cb
return cbfs_ro_type_alloc(name, NULL, NULL, size_out, type);
}
static inline void *cbfs_unverified_area_map(const char *area, const char *name,
size_t *size_out)
{
return _cbfs_unverified_area_alloc(area, name, NULL, NULL, size_out);
}
static inline size_t _cbfs_load(const char *name, void *buf, size_t size, bool force_ro,
enum cbfs_type *type)
{
@ -281,6 +311,16 @@ static inline size_t cbfs_ro_type_load(const char *name, void *buf, size_t size,
return _cbfs_load(name, buf, size, true, type);
}
static inline size_t cbfs_unverified_area_load(const char *area, const char *name,
void *buf, size_t size)
{
struct _cbfs_default_allocator_arg arg = { .buf = buf, .buf_size = size };
if (_cbfs_unverified_area_alloc(area, name, _cbfs_default_allocator, &arg, &size))
return size;
else
return 0;
}
static inline void *cbfs_cbmem_alloc(const char *name, uint32_t cbmem_id, size_t *size_out)
{
return cbfs_type_cbmem_alloc(name, cbmem_id, size_out, NULL);
@ -305,6 +345,13 @@ static inline void *cbfs_ro_type_cbmem_alloc(const char *name, uint32_t cbmem_id
size_out, type);
}
static inline void *cbfs_unverified_area_cbmem_alloc(const char *area, const char *name,
uint32_t cbmem_id, size_t *size_out)
{
return _cbfs_unverified_area_alloc(area, name, _cbfs_cbmem_allocator,
(void *)(uintptr_t)cbmem_id, size_out);
}
static inline size_t cbfs_get_size(const char *name)
{
union cbfs_mdata mdata;