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authorLucas De Marchi <lucas.demarchi@intel.com>2015-02-18 16:15:45 -0200
committerLucas De Marchi <lucas.demarchi@intel.com>2015-02-18 16:15:45 -0200
commitdcbe1846e824da3cc9facbb27691adb79cdee24a (patch)
tree39edd5c7fdad07b9ef9d60e35775f774a72bd17f
parent40ef6e69bb13522b961767d81f44aec0e83a7462 (diff)
downloadkmod-dcbe1846e824da3cc9facbb27691adb79cdee24a.tar.gz
libkmod: consider empty signature key as invalid
A segmentation fault occurs if a module has an empty key attached to its signature. This is mostly likely due to a corrupted module. The crash happens because kmod_module_get_info() assumes that kmod_module_signature_info() returns a signature of at least 1 byte. The fix is based on a patch from Tobias Stoeckmann <tobias@stoeckmann.org>, but rather than changing kmod_module_get_info() to fix the crash, this changes kmod_module_signature_info() to consider the signature as invalid.
-rw-r--r--libkmod/libkmod-signature.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/libkmod/libkmod-signature.c b/libkmod/libkmod-signature.c
index 2260cc6..5577305 100644
--- a/libkmod/libkmod-signature.c
+++ b/libkmod/libkmod-signature.c
@@ -124,7 +124,8 @@ bool kmod_module_signature_info(const struct kmod_file *file, struct kmod_signat
modsig->id_type >= PKEY_ID_TYPE__LAST)
return false;
sig_len = be32toh(get_unaligned(&modsig->sig_len));
- if (size < (int64_t)(modsig->signer_len + modsig->key_id_len + sig_len))
+ if (sig_len == 0 ||
+ size < (int64_t)(modsig->signer_len + modsig->key_id_len + sig_len))
return false;
size -= modsig->key_id_len + sig_len;