From 5ac0811f40976bf4339791a43c02516cc087462a Mon Sep 17 00:00:00 2001 From: Matthew Lugg Date: Mon, 17 Nov 2025 17:09:52 +0000 Subject: [PATCH] linux-user: fix mremap errors for invalid ranges If an address range given to `mremap` is invalid (exceeds addressing bounds on the guest), we were previously returning `ENOMEM`, which is not correct. The manpage and the Linux kernel implementation both agree that if `old_addr`/`old_size` refer to an invalid address, `EFAULT` is returned, and if `new_addr`/`new_size` refer to an invalid address, `EINVAL` is returned. Signed-off-by: Matthew Lugg Signed-off-by: Richard Henderson Message-ID: <20251117170954.31451-3-mlugg@mlugg.co.uk> (cherry picked from commit 2422884ec5a12037d2378f45ca1411d3f37c7081) Signed-off-by: Michael Tokarev --- linux-user/mmap.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/linux-user/mmap.c b/linux-user/mmap.c index ef3833a2bb..6163f1a0d1 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -1110,12 +1110,15 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size, int prot; void *host_addr; - if (!guest_range_valid_untagged(old_addr, old_size) || - ((flags & MREMAP_FIXED) && + if (((flags & MREMAP_FIXED) && !guest_range_valid_untagged(new_addr, new_size)) || ((flags & MREMAP_MAYMOVE) == 0 && !guest_range_valid_untagged(old_addr, new_size))) { - errno = ENOMEM; + errno = EINVAL; + return -1; + } + if (!guest_range_valid_untagged(old_addr, old_size)) { + errno = EFAULT; return -1; }