git: 73dddffc3175 - main - crt_malloc: more accurate handling of mmap(2) failure

[Konstantin Belousov]

The branch main has been updated by kib:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=73dddffc3175581ba99f6ced9a2e508a0e880e59

commit 73dddffc3175581ba99f6ced9a2e508a0e880e59
Author:     Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2021-10-15 17:59:37 +0000
Commit:     Konstantin Belousov <k...@freebsd.org>
CommitDate: 2021-10-18 22:02:47 +0000

    crt_malloc: more accurate handling of mmap(2) failure
    
    Reset both pagepool_start and pagepool_end after a mmap(2) failure,
    to avoid using invalid pagepool either for allocation or munmap(2).
    
    PR:     259076
    Noted by:       Denis Koreshkov <dynamic-w...@mail.ru>
    Reviewed by:    arichardson
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D32514
---
 libexec/rtld-elf/rtld_malloc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/libexec/rtld-elf/rtld_malloc.c b/libexec/rtld-elf/rtld_malloc.c
index 64218b5bb786..63fa6f5e2ee7 100644
--- a/libexec/rtld-elf/rtld_malloc.c
+++ b/libexec/rtld-elf/rtld_malloc.c
@@ -271,21 +271,21 @@ morepages(int n)
                }
        }
 
-       if (pagepool_start == MAP_FAILED)
-               pagepool_start = 0;
        offset = (uintptr_t)pagepool_start - rounddown2(
            (uintptr_t)pagepool_start, pagesz);
 
-       pagepool_start = mmap(0, n * pagesz, PROT_READ | PROT_WRITE,
+       addr = mmap(0, n * pagesz, PROT_READ | PROT_WRITE,
            MAP_ANON | MAP_PRIVATE, -1, 0);
-       if (pagepool_start == MAP_FAILED) {
+       if (addr == MAP_FAILED) {
 #ifdef IN_RTLD
                rtld_fdprintf(STDERR_FILENO, _BASENAME_RTLD ": morepages: "
                    "cannot mmap anonymous memory: %s\n",
                    rtld_strerror(errno));
 #endif
+               pagepool_start = pagepool_end = NULL;
                return (0);
        }
+       pagepool_start = addr;
        pagepool_end = pagepool_start + n * pagesz;
        pagepool_start += offset;