Vigil@nce - Linux kernel: NULL pointer dereference via slhc_init
October 2015 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
A local attacker can force a NULL pointer to be dereferenced in the slhc_init() function of the Linux kernel, in order to trigger a denial of service.
Impacted products: Linux.
Creation date: 12/10/2015.
DESCRIPTION OF THE VULNERABILITY
The Linux kernel implements the PPPIOCSMAXCID ioctl, which defines the maximal size of entries for PPP compression.
This ioctl calls the slhc_init() function of the drivers/net/slip/slhc.c file. However, if the size is too large, the comp->tstate pointer becomes NULL, and this function does not check if this pointer is NULL, before using it.
A local attacker can therefore force a NULL pointer to be dereferenced in the slhc_init() function of the Linux kernel, in order to trigger a denial of service.
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