Commit 103b1e7ce8cc ("bootm: bound-check OS index in
bootm_os_get_boot_func()") added a range check to the shared accessor so
an out-of-range OS id can no longer drive an out-of-bounds read of
boot_os[]. That accessor is reached by every image format, but only a
legacy uImage can deliver an unchecked value. bootm_find_os() takes the
raw 8-bit ih_os byte straight from image_get_os() for legacy images,
whereas the FIT path reaches the accessor only after fit_image_load()
has rejected any image whose os is not one of the supported types, and
the Android path hardcodes IH_OS_LINUX. The check can therefore never
fail for FIT, where it only adds confusion and code.Move the test to the legacy branch of bootm_find_os(), rejecting an out-of-range OS where the untrusted byte enters. This keeps the FIT path clear and lets the check be compiled out when CONFIG_LEGACY_IMAGE_FORMAT is disabled. A valid OS id that has no handler is still reported by the existing NULL return path in bootm_run_states(). Suggested-by: Simon Glass <[email protected]> Signed-off-by: Aristo Chen <[email protected]> --- boot/bootm.c | 4 ++++ boot/bootm_os.c | 2 -- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/boot/bootm.c b/boot/bootm.c index 4c260a5f5ce..f9f0b2e918a 100644 --- a/boot/bootm.c +++ b/boot/bootm.c @@ -330,6 +330,10 @@ static int bootm_find_os(const char *cmd_name, const char *addr_fit) images.os.type = image_get_type(os_hdr); images.os.comp = image_get_comp(os_hdr); images.os.os = image_get_os(os_hdr); + if (images.os.os >= IH_OS_COUNT) { + printf("Unsupported OS type %d\n", images.os.os); + return 1; + } images.os.end = image_get_image_end(os_hdr); images.os.load = image_get_load(os_hdr); diff --git a/boot/bootm_os.c b/boot/bootm_os.c index 69aa577a2fc..ae20b555f5c 100644 --- a/boot/bootm_os.c +++ b/boot/bootm_os.c @@ -599,7 +599,5 @@ int boot_selected_os(int state, struct bootm_info *bmi, boot_os_fn *boot_fn) boot_os_fn *bootm_os_get_boot_func(int os) { - if (os < 0 || os >= ARRAY_SIZE(boot_os)) - return NULL; return boot_os[os]; } -- 2.43.0
