From b8002058c45a50d893c51cf62ec96c70128fc1eb Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Thu, 3 Aug 2023 23:44:47 +0200 Subject: linux-user: Fix openat() emulation to correctly detect accesses to /proc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In qemu we catch accesses to files like /proc/cpuinfo or /proc/net/route and return to the guest contents which would be visible on a real system (instead what the host would show). This patch fixes a bug, where for example the accesses cat /proc////cpuinfo or cd /proc && cat cpuinfo will not be recognized by qemu and where qemu will wrongly show the contents of the host's /proc/cpuinfo file. Signed-off-by: Helge Deller Reviewed-by: Daniel P. Berrangé Message-Id: <20230803214450.647040-2-deller@gmx.de> Reviewed-by: Richard Henderson Signed-off-by: Richard Henderson --- linux-user/syscall.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'linux-user/syscall.c') diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 12ebc70df5..9353268cc1 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -8557,9 +8557,12 @@ static int open_hardware(CPUArchState *cpu_env, int fd) } #endif -int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *pathname, + +int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *fname, int flags, mode_t mode, bool safe) { + g_autofree char *proc_name = NULL; + const char *pathname; struct fake_open { const char *filename; int (*fill)(CPUArchState *cpu_env, int fd); @@ -8585,6 +8588,14 @@ int do_guest_openat(CPUArchState *cpu_env, int dirfd, const char *pathname, { NULL, NULL, NULL } }; + /* if this is a file from /proc/ filesystem, expand full name */ + proc_name = realpath(fname, NULL); + if (proc_name && strncmp(proc_name, "/proc/", 6) == 0) { + pathname = proc_name; + } else { + pathname = fname; + } + if (is_proc_myself(pathname, "exe")) { if (safe) { return safe_openat(dirfd, exec_path, flags, mode); -- cgit v1.2.3