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| author | Zijun Hu <quic_zijuhu@quicinc.com> | 2024-05-30 16:14:37 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-08-03 09:54:24 +0300 |
| commit | 57fe01d3d04276875c7e3a6dc763517fc05b8762 (patch) | |
| tree | 15cfd3747554f807d155a8009556c22b4d9159ba | |
| parent | f7150b2d5ec34abb95745651be75e5d596720bb7 (diff) | |
| download | linux-57fe01d3d04276875c7e3a6dc763517fc05b8762.tar.xz | |
kobject_uevent: Fix OOB access within zap_modalias_env()
commit dd6e9894b451e7c85cceb8e9dc5432679a70e7dc upstream.
zap_modalias_env() wrongly calculates size of memory block to move, so
will cause OOB memory access issue if variable MODALIAS is not the last
one within its @env parameter, fixed by correcting size to memmove.
Fixes: 9b3fa47d4a76 ("kobject: fix suppressing modalias in uevents delivered over netlink")
Cc: stable@vger.kernel.org
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Reviewed-by: Lk Sii <lk_sii@163.com>
Link: https://lore.kernel.org/r/1717074877-11352-1-git-send-email-quic_zijuhu@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | lib/kobject_uevent.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index 7c44b7ae4c5c..d397b1ad5ccf 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -432,8 +432,23 @@ static void zap_modalias_env(struct kobj_uevent_env *env) len = strlen(env->envp[i]) + 1; if (i != env->envp_idx - 1) { + /* @env->envp[] contains pointers to @env->buf[] + * with @env->buflen chars, and we are removing + * variable MODALIAS here pointed by @env->envp[i] + * with length @len as shown below: + * + * 0 @env->buf[] @env->buflen + * --------------------------------------------- + * ^ ^ ^ ^ + * | |-> @len <-| target block | + * @env->envp[0] @env->envp[i] @env->envp[i + 1] + * + * so the "target block" indicated above is moved + * backward by @len, and its right size is + * @env->buflen - (@env->envp[i + 1] - @env->envp[0]). + */ memmove(env->envp[i], env->envp[i + 1], - env->buflen - len); + env->buflen - (env->envp[i + 1] - env->envp[0])); for (j = i; j < env->envp_idx - 1; j++) env->envp[j] = env->envp[j + 1] - len; |