From: Konrad Beckmann konrad.beckmann@gmail.com
A specially crafted FIT image leads to memory corruption in the stack when using the verified boot feature. The function fit_config_check_sig has a logic error that makes it possible to write past the end of the stack allocated array node_inc. This could potentially be used to bypass the signature check when using verified boot.
This change ensures that the number of strings is correct when counted.
Signed-off-by: Konrad Beckmann konrad.beckmann@gmail.com --- common/image-sig.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/common/image-sig.c b/common/image-sig.c index 5a269d3289bf..5d860e126637 100644 --- a/common/image-sig.c +++ b/common/image-sig.c @@ -334,6 +334,11 @@ int fit_config_check_sig(const void *fit, int noffset, int required_keynode, return -1; }
+ if (prop && prop_len > 0 && prop[prop_len - 1] != '\0') { + *err_msgp = "hashed-nodes property must be null-terminated"; + return -1; + } + /* Add a sanity check here since we are using the stack */ if (count > IMAGE_MAX_HASHED_NODES) { *err_msgp = "Number of hashed nodes exceeds maximum";