efi/printf: Abort on invalid format (f97ca2c8) · Commits · 戴 / test

If we get an invalid conversion specifier, bail out instead of trying to fix it up. The format string likely has a typo or assumed we support something that we don't, in either case the remaining arguments won't match up with the remaining format string. Signed-off-by:

Arvind Sankar <nivedita@alum.mit.edu> Link: https://lore.kernel.org/r/20200518190716.751506-16-nivedita@alum.mit.edu Signed-off-by:

Ard Biesheuvel <ardb@kernel.org>

drivers/firmware/efi/libstub/vsprintf.c

+8 −6

Original line number	Diff line number	Diff line
		@@ -359,12 +359,13 @@ int vsprintf(char buf, const char fmt, va_list ap)
		break;

		default:
		*str++ = '%';
		if (*fmt)
		str++ = fmt;
		else
		--fmt;
		continue;
		/*
		* Bail out if the conversion specifier is invalid.
		* There's probably a typo in the format string and the
		* remaining specifiers are unlikely to match up with
		* the arguments.
		*/
		goto fail;
		}
		if (*fmt == 'p') {
		num = (unsigned long)va_arg(args, void *);
		@@ -434,6 +435,7 @@ output:
		while (field_width-- > 0)
		*str++ = ' ';
		}
		fail:
		*str = '\0';

		va_end(args);

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