From: Oleg Nesterov <oleg@xxxxxxxxxx> Subject: exec: binfmt_misc: kill the onstack iname[BINPRM_BUF_SIZE] array After the previous change "fmt" can't go away, we can kill iname/iname_addr and use fmt->interpreter. Link: http://lkml.kernel.org/r/20170922143653.GA17232@xxxxxxxxxx Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Ben Woodard <woodard@xxxxxxxxxx> Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> Cc: Jim Foraker <foraker1@xxxxxxxx> Cc: <tdhooge@xxxxxxxx> Cc: Travis Gummels <tgummels@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/binfmt_misc.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff -puN fs/binfmt_misc.c~exec-binfmt_misc-kill-the-onstack-iname-array fs/binfmt_misc.c --- a/fs/binfmt_misc.c~exec-binfmt_misc-kill-the-onstack-iname-array +++ a/fs/binfmt_misc.c @@ -54,7 +54,7 @@ typedef struct { int size; /* size of magic/mask */ char *magic; /* magic or filename extension */ char *mask; /* mask, NULL for exact match */ - char *interpreter; /* filename of interpreter */ + const char *interpreter; /* filename of interpreter */ char *name; struct dentry *dentry; struct file *interp_file; @@ -131,8 +131,6 @@ static int load_misc_binary(struct linux { Node *fmt; struct file *interp_file = NULL; - char iname[BINPRM_BUF_SIZE]; - const char *iname_addr = iname; int retval; int fd_binary = -1; @@ -143,10 +141,8 @@ static int load_misc_binary(struct linux /* to keep locking time low, we copy the interpreter string */ read_lock(&entries_lock); fmt = check_file(bprm); - if (fmt) { + if (fmt) dget(fmt->dentry); - strlcpy(iname, fmt->interpreter, BINPRM_BUF_SIZE); - } read_unlock(&entries_lock); if (!fmt) return retval; @@ -198,13 +194,13 @@ static int load_misc_binary(struct linux bprm->argc++; /* add the interp as argv[0] */ - retval = copy_strings_kernel(1, &iname_addr, bprm); + retval = copy_strings_kernel(1, &fmt->interpreter, bprm); if (retval < 0) goto error; bprm->argc++; /* Update interp in case binfmt_script needs it. */ - retval = bprm_change_interp(iname, bprm); + retval = bprm_change_interp(fmt->interpreter, bprm); if (retval < 0) goto error; @@ -213,7 +209,7 @@ static int load_misc_binary(struct linux if (!IS_ERR(interp_file)) deny_write_access(interp_file); } else { - interp_file = open_exec(iname); + interp_file = open_exec(fmt->interpreter); } retval = PTR_ERR(interp_file); if (IS_ERR(interp_file)) _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
