On Linux depending on flags the source, type and data my be ignored. We already don't check data and allow source to be NULL. Normally when type is ignored an application will provide an empty string "". But sometimes NULL is passed (like for source). So we should also allow type to be NULL to prevent false positives. diff --git a/coregrind/m_syswrap/syswrap-linux.c b/coregrind/m_syswrap/syswrap-linux.c index 6f3917830fa4..afd4a618b12f 100644 --- a/coregrind/m_syswrap/syswrap-linux.c +++ b/coregrind/m_syswrap/syswrap-linux.c @@ -1000,7 +1000,8 @@ PRE(sys_mount) { // Nb: depending on 'flags', the 'type' and 'data' args may be ignored. // We are conservative and check everything, except the memory pointed to - // by 'data'. + // by 'data'. And since both 'source' and 'type' may be ignored, we allow + // them to be NULL. *flags |= SfMayBlock; PRINT("sys_mount( %#" FMT_REGWORD "x(%s), %#" FMT_REGWORD "x(%s), %#" FMT_REGWORD "x(%s), %#" FMT_REGWORD "x, %#" FMT_REGWORD "x )", @@ -1012,7 +1013,8 @@ PRE(sys_mount) if (ARG1) PRE_MEM_RASCIIZ( "mount(source)", ARG1); PRE_MEM_RASCIIZ( "mount(target)", ARG2); - PRE_MEM_RASCIIZ( "mount(type)", ARG3); + if (ARG3) + PRE_MEM_RASCIIZ( "mount(type)", ARG3); } PRE(sys_oldumount)
commit ff6e14ab798af0628c54c6a704c1cb8844a79419 Author: Mark Wielaard <mark@klomp.org> Date: Fri May 9 00:21:25 2025 +0200 mount syscall param filesystemtype may be NULL On Linux the mount syscall, depending on flags provided, the source, type and data my be ignored. We already don't check data and allow source to be NULL. Normally when type is ignored an application will provide an empty string "". But sometimes NULL is passed (like for source). So we now also allow type to be NULL to prevent false positives. Adjust the linux/scalar.c tests so the type param is still unaddressable. https://bugs.kde.org/show_bug.cgi?id=503914