From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Darren Kenny Date: Tue, 3 Nov 2020 16:43:37 +0000 Subject: [PATCH] libgcrypt/mpi: Fix possible unintended sign extension The array of unsigned char gets promoted to a signed 32-bit int before it is finally promoted to a size_t. There is the possibility that this may result in the signed-bit being set for the intermediate signed 32-bit int. We should ensure that the promotion is to the correct type before we bitwise-OR the values. Fixes: CID 96697 Signed-off-by: Darren Kenny Reviewed-by: Daniel Kiper --- grub-core/lib/libgcrypt/mpi/mpicoder.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/grub-core/lib/libgcrypt/mpi/mpicoder.c b/grub-core/lib/libgcrypt/mpi/mpicoder.c index a3435ed14..7ecad27b2 100644 --- a/grub-core/lib/libgcrypt/mpi/mpicoder.c +++ b/grub-core/lib/libgcrypt/mpi/mpicoder.c @@ -458,7 +458,7 @@ gcry_mpi_scan (struct gcry_mpi **ret_mpi, enum gcry_mpi_format format, if (len && len < 4) return gcry_error (GPG_ERR_TOO_SHORT); - n = (s[0] << 24 | s[1] << 16 | s[2] << 8 | s[3]); + n = ((size_t)s[0] << 24 | (size_t)s[1] << 16 | (size_t)s[2] << 8 | (size_t)s[3]); s += 4; if (len) len -= 4;