Messages in this thread Patch in this message | | | From | Eric Paris <> | Subject | [PATCH =-v3 11/21] fanotify: give a special access permission check | Date | Wed, 12 Nov 2008 11:11:24 -0500 |
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add a special FANOTIFY_ACCESS_EXEC_PERM check. This will be applied any place a process tries to access a file with execute permissions. Mainly sys_execve, sys_uselib, and mmap'ing a file for exec.
Signed-off-by: Eric Paris <eparis@redhat.com> ---
fs/aio.c | 4 ++-- fs/exec.c | 10 ++++++++++ fs/read_write.c | 2 +- include/linux/fanotify.h | 6 ++++-- mm/mmap.c | 7 +++++++ mm/mprotect.c | 6 ++++++ mm/nommu.c | 7 +++++++ 7 files changed, 37 insertions(+), 5 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c index 008de79..6395403 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1455,7 +1455,7 @@ static ssize_t aio_setup_iocb(struct kiocb *kiocb) ret = security_file_permission(file, MAY_READ); if (unlikely(ret)) break; - ret = fanotify(file, FAN_ACCESS_PERM); + ret = fanotify(file, FAN_ACCESS_NOEXEC_PERM); if (unlikely(ret)) break; ret = aio_setup_single_vector(kiocb); @@ -1490,7 +1490,7 @@ static ssize_t aio_setup_iocb(struct kiocb *kiocb) ret = security_file_permission(file, MAY_READ); if (unlikely(ret)) break; - ret = fanotify(file, FAN_ACCESS_PERM); + ret = fanotify(file, FAN_ACCESS_NOEXEC_PERM); if (unlikely(ret)) break; ret = aio_setup_vectored_rw(READ, kiocb); diff --git a/fs/exec.c b/fs/exec.c index 8f56995..3d88fa3 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -137,6 +137,11 @@ asmlinkage long sys_uselib(const char __user * library) goto out; fsnotify_open_exec(file); + error = fanotify(file, FAN_ACCESS_EXEC_PERM); + if (error) { + fput(file); + goto out; + } error = -ENOEXEC; if(file->f_op) { @@ -691,6 +696,11 @@ struct file *open_exec(const char *name) return file; fsnotify_open_exec(file); + err = fanotify(file, FAN_ACCESS_EXEC_PERM); + if (err) { + fput(file); + goto out; + } err = deny_write_access(file); if (err) { diff --git a/fs/read_write.c b/fs/read_write.c index 6f8cf69..5100cd2 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -225,7 +225,7 @@ int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count if (retval) return retval; if (read_write == READ) { - retval = fanotify(file, FAN_ACCESS_PERM); + retval = fanotify(file, FAN_ACCESS_NOEXEC_PERM); if (retval) return retval; } diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h index 83c3d5e..efc62e9 100644 --- a/include/linux/fanotify.h +++ b/include/linux/fanotify.h @@ -18,8 +18,9 @@ #define FAN_OPEN_EXEC 0x00000020 /* File was opened with the intention of being exec'ed */ /* userspace may also request blocking for permission checks for open and read */ -#define FAN_ACCESS_PERM 0x00000100 -#define FAN_OPEN_PERM 0x00000200 +#define FAN_ACCESS_NOEXEC_PERM 0x00000100 +#define FAN_ACCESS_EXEC_PERM 0x00000200 +#define FAN_OPEN_PERM 0x00000400 /* FIXME currently Q's have no limit.... */ #define FAN_Q_OVERFLOW 0x80000000 /* Event queued overflowed */ @@ -27,6 +28,7 @@ /* helper events */ #define FAN_CLOSE (FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE) /* close */ #define FAN_OPEN (FAN_OPEN_NOEXEC | FAN_OPEN_EXEC) /* open */ +#define FAN_ACCESS_PERM (FAN_ACCESS_NOEXEC_PERM | FAN_ACCESS_EXEC_PERM) /* access perm */ /* * All of the events - we build the list by hand so that we can add flags in diff --git a/mm/mmap.c b/mm/mmap.c index de14ac2..8013252 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -18,6 +18,7 @@ #include <linux/init.h> #include <linux/file.h> #include <linux/fs.h> +#include <linux/fanotify.h> #include <linux/personality.h> #include <linux/security.h> #include <linux/hugetlb.h> @@ -1027,6 +1028,12 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, default: return -EINVAL; } + + if (prot & PROT_EXEC) { + error = fanotify(file, FAN_ACCESS_EXEC_PERM); + if (error) + return error; + } } else { switch (flags & MAP_TYPE) { case MAP_SHARED: diff --git a/mm/mprotect.c b/mm/mprotect.c index fded06f..af1da2d 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -16,6 +16,7 @@ #include <linux/fs.h> #include <linux/highmem.h> #include <linux/security.h> +#include <linux/fanotify.h> #include <linux/mempolicy.h> #include <linux/personality.h> #include <linux/syscalls.h> @@ -294,6 +295,11 @@ sys_mprotect(unsigned long start, size_t len, unsigned long prot) if (error) goto out; + if (vma->vm_file && (prot & PROT_EXEC)) + error = fanotify(vma->vm_file, FAN_ACCESS_EXEC_PERM); + if (error) + goto out; + tmp = vma->vm_end; if (tmp > end) tmp = end; diff --git a/mm/nommu.c b/mm/nommu.c index 7695dc8..d376916 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -18,6 +18,7 @@ #include <linux/mman.h> #include <linux/swap.h> #include <linux/file.h> +#include <linux/fanotify.h> #include <linux/highmem.h> #include <linux/pagemap.h> #include <linux/slab.h> @@ -731,6 +732,12 @@ static int validate_mmap_request(struct file *file, /* backing file is not executable, try to copy */ capabilities &= ~BDI_CAP_MAP_DIRECT; } + + if (prot & PROT_EXEC) { + ret = fanotify(file, FAN_ACCESS_EXEC_PERM); + if (ret) + return ret; + } } else { /* anonymous mappings are always memory backed and can be
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