From: Jan Beulich Date: Thu, 20 Jun 2024 15:34:56 +0000 (+0200) Subject: libelf: avoid UB in elf_xen_feature_{get,set}() X-Git-Tag: 4.19.0-rc1~35 X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=9e7c26ad8532c3efda174dee5ab8bdbeef1e4f6d;p=xen.git libelf: avoid UB in elf_xen_feature_{get,set}() When the left shift amount is up to 31, the shifted quantity wants to be of unsigned int (or wider) type. While there also adjust types: get doesn't alter the array and returns a boolean, while both don't really accept negative "nr". Drop a stray blank each as well. Signed-off-by: Jan Beulich Reviewed-by: Andrew Cooper Release-Acked-By: Oleksii Kurochko --- diff --git a/xen/include/xen/libelf.h b/xen/include/xen/libelf.h index a0675a4dc3..a99d33c251 100644 --- a/xen/include/xen/libelf.h +++ b/xen/include/xen/libelf.h @@ -445,13 +445,13 @@ struct elf_dom_parms { uint64_t virt_kend; }; -static inline void elf_xen_feature_set(int nr, uint32_t * addr) +static inline void elf_xen_feature_set(unsigned int nr, uint32_t *addr) { - addr[nr >> 5] |= 1 << (nr & 31); + addr[nr >> 5] |= 1U << (nr & 31); } -static inline int elf_xen_feature_get(int nr, uint32_t * addr) +static inline bool elf_xen_feature_get(unsigned int nr, const uint32_t *addr) { - return !!(addr[nr >> 5] & (1 << (nr & 31))); + return addr[nr >> 5] & (1U << (nr & 31)); } elf_errorstatus elf_xen_parse_features(const char *features,