From e8814c811132a70f9b55418f7567378a34ad3883 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 Signed-off-by: Stefan Sørensen --- grub-core/lib/libgcrypt-grub/mpi/mpicoder.c | 2 +- grub-core/lib/libgcrypt/mpi/mpicoder.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/grub-core/lib/libgcrypt-grub/mpi/mpicoder.c b/grub-core/lib/libgcrypt-grub/mpi/mpicoder.c index 3d55dfc..faf1cd6 100644 --- a/grub-core/lib/libgcrypt-grub/mpi/mpicoder.c +++ b/grub-core/lib/libgcrypt-grub/mpi/mpicoder.c @@ -460,7 +460,7 @@ 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; diff --git a/grub-core/lib/libgcrypt/mpi/mpicoder.c b/grub-core/lib/libgcrypt/mpi/mpicoder.c index a3435ed..7ecad27 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; -- 2.14.2