@@ -1257,7 +1257,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
}
reloc_func_desc = interp_load_addr;
- allow_write_access(interpreter);
+ exe_file_allow_write_access(interpreter);
fput(interpreter);
kfree(interp_elf_ex);
@@ -1354,7 +1354,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
kfree(interp_elf_ex);
kfree(interp_elf_phdata);
out_free_file:
- allow_write_access(interpreter);
+ exe_file_allow_write_access(interpreter);
if (interpreter)
fput(interpreter);
out_free_ph:
@@ -394,7 +394,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
goto error;
}
- allow_write_access(interpreter);
+ exe_file_allow_write_access(interpreter);
fput(interpreter);
interpreter = NULL;
}
@@ -467,7 +467,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
error:
if (interpreter) {
- allow_write_access(interpreter);
+ exe_file_allow_write_access(interpreter);
fput(interpreter);
}
kfree(interpreter_name);
@@ -912,7 +912,7 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags)
path_noexec(&file->f_path))
return ERR_PTR(-EACCES);
- err = deny_write_access(file);
+ err = exe_file_deny_write_access(file);
if (err)
return ERR_PTR(err);
@@ -927,7 +927,7 @@ static struct file *do_open_execat(int fd, struct filename *name, int flags)
* Returns ERR_PTR on failure or allocated struct file on success.
*
* As this is a wrapper for the internal do_open_execat(), callers
- * must call allow_write_access() before fput() on release. Also see
+ * must call exe_file_allow_write_access() before fput() on release. Also see
* do_close_execat().
*/
struct file *open_exec(const char *name)
@@ -1471,7 +1471,7 @@ static void do_close_execat(struct file *file)
{
if (!file)
return;
- allow_write_access(file);
+ exe_file_allow_write_access(file);
fput(file);
}
@@ -1797,7 +1797,7 @@ static int exec_binprm(struct linux_binprm *bprm)
bprm->file = bprm->interpreter;
bprm->interpreter = NULL;
- allow_write_access(exec);
+ exe_file_allow_write_access(exec);
if (unlikely(bprm->have_execfd)) {
if (bprm->executable) {
fput(exec);
@@ -3089,6 +3089,23 @@ static inline void allow_write_access(struct file *file)
if (file)
atomic_inc(&file_inode(file)->i_writecount);
}
+
+/*
+ * Do not prevent write to executable file when watched by pre-content events.
+ */
+static inline int exe_file_deny_write_access(struct file *exe_file)
+{
+ if (unlikely(FMODE_FSNOTIFY_HSM(exe_file->f_mode)))
+ return 0;
+ return deny_write_access(exe_file);
+}
+static inline void exe_file_allow_write_access(struct file *exe_file)
+{
+ if (unlikely(FMODE_FSNOTIFY_HSM(exe_file->f_mode)))
+ return;
+ allow_write_access(exe_file);
+}
+
static inline bool inode_is_open_for_write(const struct inode *inode)
{
return atomic_read(&inode->i_writecount) > 0;
@@ -625,8 +625,8 @@ static void dup_mm_exe_file(struct mm_struct *mm, struct mm_struct *oldmm)
* We depend on the oldmm having properly denied write access to the
* exe_file already.
*/
- if (exe_file && deny_write_access(exe_file))
- pr_warn_once("deny_write_access() failed in %s\n", __func__);
+ if (exe_file && exe_file_deny_write_access(exe_file))
+ pr_warn_once("exe_file_deny_write_access() failed in %s\n", __func__);
}
#ifdef CONFIG_MMU
@@ -1424,13 +1424,13 @@ int set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
* We expect the caller (i.e., sys_execve) to already denied
* write access, so this is unlikely to fail.
*/
- if (unlikely(deny_write_access(new_exe_file)))
+ if (unlikely(exe_file_deny_write_access(new_exe_file)))
return -EACCES;
get_file(new_exe_file);
}
rcu_assign_pointer(mm->exe_file, new_exe_file);
if (old_exe_file) {
- allow_write_access(old_exe_file);
+ exe_file_allow_write_access(old_exe_file);
fput(old_exe_file);
}
return 0;
@@ -1471,7 +1471,7 @@ int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
return ret;
}
- ret = deny_write_access(new_exe_file);
+ ret = exe_file_deny_write_access(new_exe_file);
if (ret)
return -EACCES;
get_file(new_exe_file);
@@ -1483,7 +1483,7 @@ int replace_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
mmap_write_unlock(mm);
if (old_exe_file) {
- allow_write_access(old_exe_file);
+ exe_file_allow_write_access(old_exe_file);
fput(old_exe_file);
}
return 0;
Commit 2a010c412853 ("fs: don't block i_writecount during exec") removed the legacy behavior of getting ETXTBSY on attempt to open and executable file for write while it is being executed. This commit was reverted because an application that depends on this legacy behavior was broken by the change. We need to allow HSM writing into executable files while executed to fill their content on-the-fly. To that end, disable the ETXTBSY legacy behavior for files that are watched by pre-content events. This change is not expected to cause regressions with existing systems which do not have any pre-content event listeners. Signed-off-by: Amir Goldstein <amir73il@gmail.com> --- Jan, This patch is on top of your fsnotify_hsm rebased branch. It passed LTP sanity tests, but did not test filling an executable on-the-fly. Josef, can you verify that this works as expected. Also pushed to fsnotify_hsm branch in my github. Thanks, Amir. fs/binfmt_elf.c | 4 ++-- fs/binfmt_elf_fdpic.c | 4 ++-- fs/exec.c | 8 ++++---- include/linux/fs.h | 17 +++++++++++++++++ kernel/fork.c | 12 ++++++------ 5 files changed, 31 insertions(+), 14 deletions(-)