5.4-stable review patch. If anyone has any objections, please let me know.
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From: Zijun Hu quic_zijuhu@quicinc.com
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@quic... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- lib/kobject_uevent.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
--- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -432,8 +432,23 @@ static void zap_modalias_env(struct kobj 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;