From ab482a557d4a34a913b49fad4b3bd3bf7f1d70bd Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Wed, 24 Jul 2024 14:05:13 -0700 Subject: [PATCH] linux: Update the mremap C implementation [BZ #31968] Update the mremap C implementation to support the optional argument for MREMAP_DONTUNMAP added in Linux 5.7 since it may not always be correct to implement a variadic function as a non-variadic function on all Linux targets. Return MAP_FAILED and set errno to EINVAL for unknown flag bits. This fixes BZ #31968. Note: A test must be added when a new flag bit is introduced. Signed-off-by: H.J. Lu Reviewed-by: Adhemerval Zanella (cherry picked from commit 6c40cb0e9f893d49dc7caee580a055de53562206) --- NEWS | 1 + sysdeps/unix/sysv/linux/mremap.c | 14 +++++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/NEWS b/NEWS index 68f10fdfc73..ed2fe84fa0f 100644 --- a/NEWS +++ b/NEWS @@ -101,6 +101,7 @@ The following bugs are resolved with this release: [31476] resolv: Track single-request fallback via _res._flags [31890] resolv: Allow short error responses to match any DNS query [31965] rseq extension mechanism does not work as intended + [31968] mremap implementation in C does not handle arguments correctly Version 2.36 diff --git a/sysdeps/unix/sysv/linux/mremap.c b/sysdeps/unix/sysv/linux/mremap.c index e829a29dbdd..c48932e5693 100644 --- a/sysdeps/unix/sysv/linux/mremap.c +++ b/sysdeps/unix/sysv/linux/mremap.c @@ -20,6 +20,12 @@ #include #include #include +#include + +#define MREMAP_KNOWN_BITS \ + (MREMAP_MAYMOVE \ + | MREMAP_FIXED \ + | MREMAP_DONTUNMAP) void * __mremap (void *addr, size_t old_len, size_t new_len, int flags, ...) @@ -27,7 +33,13 @@ __mremap (void *addr, size_t old_len, size_t new_len, int flags, ...) va_list va; void *new_addr = NULL; - if (flags & MREMAP_FIXED) + if (flags & ~(MREMAP_KNOWN_BITS)) + { + __set_errno (EINVAL); + return MAP_FAILED; + } + + if (flags & (MREMAP_FIXED | MREMAP_DONTUNMAP)) { va_start (va, flags); new_addr = va_arg (va, void *); -- 2.47.2