On 8/29/23 18:45, Nick Desaulniers wrote:
Helge, A recent change in clang made it better about spotting snprintf that will result in truncation. Nathan reported the following instances: drivers/video/fbdev/neofb.c:1959:3: warning: 'snprintf' will always be truncated; specified size is 16, but format string expands to at least 17 [-Wfortify-source] drivers/video/fbdev/neofb.c:1963:3: warning: 'snprintf' will always be truncated; specified size is 16, but format string expands to at least 18 [-Wfortify-source] drivers/video/fbdev/neofb.c:1967:3: warning: 'snprintf' will always be truncated; specified size is 16, but format string expands to at least 17 [-Wfortify-source] drivers/video/fbdev/neofb.c:1971:3: warning: 'snprintf' will always be truncated; specified size is 16, but format string expands to at least 17 [-Wfortify-source] drivers/video/fbdev/neofb.c:1978:3: warning: 'snprintf' will always be truncated; specified size is 16, but format string expands to at least 18 [-Wfortify-source] drivers/video/fbdev/neofb.c:1985:3: warning: 'snprintf' will always be truncated; specified size is 16, but format string expands to at least 17 [-Wfortify-source] drivers/video/fbdev/neofb.c:1992:3: warning: 'snprintf' will always be truncated; specified size is 16, but format string expands to at least 18 [-Wfortify-source] https://github.com/ClangBuiltLinux/linux/issues/1923 Clang is right here. `info->fix.id` is declared as `char id[16];` so indeed string literals like "MagicGraph 256AV+" indeed lead to truncation. But this is declared in include/uapi/linux/fb.h; I assume those headers cant be changed? Can the strings be shortened then? Is it perhaps time to delete this driver? I see AKPM mentioned alluded to this in commit 0e90454 ("neofb: avoid overwriting fb_info fields") (Also, snprintf probably isn't necessary for string literals that don't contain format strings)
It's just an ID field, so I don't think we need the full name of the card. So using strscpy() and shorten the name, e.g. "MagicGr. 256XL+" instead of "MagicGraph 256XL+" is probably the most simple solution? Anyone want to send a patch? Helge
