https://bugs.kde.org/show_bug.cgi?id=435375
Bug ID: 435375
Summary: Syscall param socketcall.setsockopt(optval) points to
uninitialised byte(s) (Multicast API)
Product: valgrind
Version: 3.14.0
Platform: Other
OS: Other
Status: REPORTED
Severity: normal
Priority: NOR
Component: memcheck
Assignee: jsew...@acm.org
Reporter: uglymo...@wizdom.nu
Target Milestone: ---
Seems that Valgrind is not recognizing padding in struct group_req and or
struct sockaddr_in/storage.
Code to reproduce:
struct group_req GrpReq;
struct sockaddr_in Grp = { AF_INET, 0, {mcastaddr}, {0} };
GrpReq.gr_interface = IfDp ? if_nametoindex(IfDp->Name) : 0;
memcpy(&GrpReq.gr_group, &Grp, sizeof(Grp));
setsockopt(mrouterFD, IPPROTO_IP, MCAST_JOIN_GROUP, &GrpReq, sizeof(GrpReq))
Valgrind is erroring on:
==30163== Syscall param socketcall.setsockopt(optval) points to uninitialised
byte(s)
==30163== at 0x4935CD8: setsockopt (syscall-template.S:78)
==30163== by 0x112177: k_joinleave (kern.c:108)
....
==30163== Address 0x1ffeffff2c is on thread 1's stack
==30163== in frame #1, created by k_joinleave (kern.c:92)
Examaning stack frame #1 shows the data used to call setsockopt is perfectly
fine:
#1 0x0000000000112178 in k_joinleave (Cmd=106, IfDp=0x49e3fa0,
mcastaddr=33554656) at kern.c:112
GrpReq = {gr_interface = 6, gr_group = {ss_family = 2,
__ss_padding = "\000\000\340\000\000\002", '\000' <repeats 16
times>,
"hZ\215\004\000\000\000\000\320\377\377\376\037\000\000\000\224\357\020\000\000\000\000\000\240?\236\004\000\000\000\000p\000\000\377\037\000\000\000X\343\022",
'\000' <repeats 14 times>,
"\320\022\000\000\000\000\000\003\000\000\000\000\000\000\000\002\000\000\000\000\000\000\000\001\000\000\000\000\000\000\000\003\000\000\000\000\000\000",
__ss_align = 1146280}}
Grp = {sin_family = 2, sin_port = 0, sin_addr = {s_addr = 33554656},
sin_zero = "\000\000\000\000\000\000\000"}
...
__ss_padding = "\000\000\340\000\000\002"
is port 0, and multicast address 224.0.0.2 (mcastaddr=33554656 / 0xE0000002)
All requirements for this setsockopt API are thus satisfied and the error is a
false positive.
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