Date: Fri, 19 Dec 2025 09:19:23 +0000 From: Olivier Certner <olce@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 2815d86103ae - stable/14 - setcred(): Fix 32-bit compatibility copy-in Message-ID: <6945189b.3f889.1a299a8a@gitrepo.freebsd.org>
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The branch stable/14 has been updated by olce: URL: https://cgit.FreeBSD.org/src/commit/?id=2815d86103ae1b0e871c0dd68bb8b3c3090a2264 commit 2815d86103ae1b0e871c0dd68bb8b3c3090a2264 Author: Olivier Certner <olce@FreeBSD.org> AuthorDate: 2025-11-14 20:20:12 +0000 Commit: Olivier Certner <olce@FreeBSD.org> CommitDate: 2025-12-19 09:16:48 +0000 setcred(): Fix 32-bit compatibility copy-in For 32-bit processes on 64-bit architectures, a difference of 'int' pointers was wrongly used as a number of bytes to copy in a memcpy() used to internally construct a 64-bit 'struct setcred' from the 32-bit variant, leading to copying only part of the 32-bit structure, and thus to requesting credentials with garbage IDs except for the real and effective user IDs. This bug was spotted by jhb@, who produced a slightly more invasive fix in D53757 (a switch to using CP() on all fields). In the interest of minimizing the diff for possible inclusion in 15.0, the commit here just limits itself to fixing the number of bytes to copy. Tested successfully on a VM with 32-bit mdo(1) (and in passing also tested that the same executable on a kernel without this change exhibits the bug in practice, in the form of setcred() failing with EINVAL). Reported by: jhb Reviewed by: jhb Fixes: ddb3eb4efe55 ("New setcred() system call and associated MAC hooks") MFC after: 3 days Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D53767 (cherry picked from commit 4872b48b175cc637ee38f645d68b8207d9335474) --- sys/kern/kern_prot.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/sys/kern/kern_prot.c b/sys/kern/kern_prot.c index c8fea2672565..9edc1fa3f02c 100644 --- a/sys/kern/kern_prot.c +++ b/sys/kern/kern_prot.c @@ -576,8 +576,8 @@ user_setcred(struct thread *td, const u_int flags, if (error != 0) return (error); /* These fields have exactly the same sizes and positions. */ - memcpy(&wcred, &wcred32, &wcred32.setcred32_copy_end - - &wcred32.setcred32_copy_start); + memcpy(&wcred, &wcred32, __rangeof(struct setcred32, + setcred32_copy_start, setcred32_copy_end)); /* Remaining fields are pointers and need PTRIN*(). */ PTRIN_CP(wcred32, wcred, sc_supp_groups); PTRIN_CP(wcred32, wcred, sc_label);help
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