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linux/block/blk-cgroup-fc-appid.c
Azeem Shaikh 20d099756b block: Replace all non-returning strlcpy with strscpy
strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230530155608.272266-1-azeemshaikh38@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-01 09:13:31 -06:00

58 lines
1.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include "blk-cgroup.h"
/**
* blkcg_set_fc_appid - set the fc_app_id field associted to blkcg
* @app_id: application identifier
* @cgrp_id: cgroup id
* @app_id_len: size of application identifier
*/
int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len)
{
struct cgroup *cgrp;
struct cgroup_subsys_state *css;
struct blkcg *blkcg;
int ret = 0;
if (app_id_len > FC_APPID_LEN)
return -EINVAL;
cgrp = cgroup_get_from_id(cgrp_id);
if (IS_ERR(cgrp))
return PTR_ERR(cgrp);
css = cgroup_get_e_css(cgrp, &io_cgrp_subsys);
if (!css) {
ret = -ENOENT;
goto out_cgrp_put;
}
blkcg = css_to_blkcg(css);
/*
* There is a slight race condition on setting the appid.
* Worst case an I/O may not find the right id.
* This is no different from the I/O we let pass while obtaining
* the vmid from the fabric.
* Adding the overhead of a lock is not necessary.
*/
strscpy(blkcg->fc_app_id, app_id, app_id_len);
css_put(css);
out_cgrp_put:
cgroup_put(cgrp);
return ret;
}
EXPORT_SYMBOL_GPL(blkcg_set_fc_appid);
/**
* blkcg_get_fc_appid - get the fc app identifier associated with a bio
* @bio: target bio
*
* On success return the fc_app_id, on failure return NULL
*/
char *blkcg_get_fc_appid(struct bio *bio)
{
if (!bio->bi_blkg || bio->bi_blkg->blkcg->fc_app_id[0] == '\0')
return NULL;
return bio->bi_blkg->blkcg->fc_app_id;
}
EXPORT_SYMBOL_GPL(blkcg_get_fc_appid);