Messages in this thread Patch in this message | | | From | Chuhong Yuan <> | Subject | [PATCH v3 7/8] userns: Replace strncmp with str_has_prefix | Date | Mon, 5 Aug 2019 20:23:46 +0800 |
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strncmp(str, const, len) is error-prone because len is easy to have typo. The example is the hard-coded len has counting error or sizeof(const) forgets - 1. So we prefer using newly introduced str_has_prefix() to substitute such strncmp to make code better.
Signed-off-by: Chuhong Yuan <hslester96@gmail.com> --- Changes in v3: - Revise the description.
kernel/user_namespace.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 8eadadc478f9..e231e902df8a 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -1138,6 +1138,7 @@ ssize_t proc_setgroups_write(struct file *file, const char __user *buf, char kbuf[8], *pos; bool setgroups_allowed; ssize_t ret; + size_t len; /* Only allow a very narrow range of strings to be written */ ret = -EINVAL; @@ -1153,12 +1154,11 @@ ssize_t proc_setgroups_write(struct file *file, const char __user *buf, /* What is being requested? */ ret = -EINVAL; - if (strncmp(pos, "allow", 5) == 0) { - pos += 5; + if ((len = str_has_prefix(pos, "allow"))) { + pos += len; setgroups_allowed = true; - } - else if (strncmp(pos, "deny", 4) == 0) { - pos += 4; + } else if ((len = str_has_prefix(pos, "deny"))) { + pos += len; setgroups_allowed = false; } else -- 2.20.1
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