Hi Christian, LGTM, thanks and thanks for the thorough description. I'm not a computer that I can apply right now, but will do so later.
This seems like a critical enough bug to do a new release, i will try to do so by the end of the week. Al On Thu, 2020-09-03 at 09:14 +0200, Christian Ehrhardt wrote: > Since 68ed819 "acpi-spmi locate driver" the initialization of > acpi_table > was done as a direct assignment on a global variable. > Later on _ipmi_acpi_get_table was restructured and now expects > malloced > memory, but the old intialization was left in place now killing the > malloced > pointer. > > It turns out that on systems without /sys/firmware/acpi/tables/SPMI > like > Dell iDRAC6/9 _ipmi_acpi_get_table then tries to assign > acpi_table_buf to it. > This leads to an access of 0x0 and a crash, for a backtrace see: > https://launchpadlibrarian.net/495892193/apport-retrace-ipmi-locate.txt > > On other hardware (with SPMI file in sysfs) there are some early > exits before > this happens. Additionally Before 094cd5ce "Audit libfreeipmi, remove > unnecessary memsets, fix +1 buffers, etc." which is in >1.6.0 there > was > another early exit in _ipmi_acpi_get_table_dev_mem as > _ipmi_acpi_get_rsdp > never returned non zero, but since that fix it can reach the bad > code. > > The old style assignment of acpi_table is wrong (writes the pointer > instead > of the pointer target) and superfluous as it is done correct at the > beginning > of _ipmi_acpi_get_table_dev_mem and between this init and the usage > no more > touched. Therefore it is safe to just remove the bad initialization. > > Signed-off-by: Christian Ehrhardt <christian.ehrha...@canonical.com> > Reported-by: jeffrey.l...@canonical.com > --- > libfreeipmi/locate/ipmi-locate-acpi-spmi.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/libfreeipmi/locate/ipmi-locate-acpi-spmi.c > b/libfreeipmi/locate/ipmi-locate-acpi-spmi.c > index 710674e53..11c688524 100644 > --- a/libfreeipmi/locate/ipmi-locate-acpi-spmi.c > +++ b/libfreeipmi/locate/ipmi-locate-acpi-spmi.c > @@ -1384,7 +1384,6 @@ _ipmi_acpi_get_table_dev_mem (ipmi_locate_ctx_t > ctx, > else > acpi_table_count = rsdt_xsdt_table_data_length / 8; > > - acpi_table = NULL; > acpi_table_length = 0; > for (i = 0, signature_table_count = 0; i < acpi_table_count; i++) > {
