Logger: Fix format string overflow in writeHeader()

[egorenar]

This problem occurred on a 32-bit ARM OpenWRT router running Linux 6.1. The method writeHeader() assumes that the size of struct timeval is 8 bytes which is not true on this machine, it is 16 bytes large. Therefore, first cast tv.tv_usec to the unsigned long type.

=========
GDB trace

(gdb) c
Continuing.

Program received signal SIGSEGV, Segmentation fault.
0xb6f4f9b4 in memchr (src=src@entry=0x3b6a, c=c@entry=0x0, n=n@entry=0x7fffffff) at src/string/memchr.c:16
16 for (; ((uintptr_t)s & ALIGN) && n && *s != c; s++, n--);
0xb6f4f98c <memchr+12>: 00 00 52 e3 cmp r2, #0
0xb6f4f990 <memchr+16>: 00 30 a0 e1 mov r3, r0
0xb6f4f994 <memchr+20>: 05 00 00 1a bne 0xb6f4f9b0 <memchr+48>
0xb6f4f998 <memchr+24>: 32 00 00 ea b 0xb6f4fa68 <memchr+232>
0xb6f4f99c <memchr+28>: 03 00 13 e3 tst r3, #3
0xb6f4f9a0 <memchr+32>: 01 20 42 e2 sub r2, r2, #1
0xb6f4f9a4 <memchr+36>: 36 00 00 0a beq 0xb6f4fa84 <memchr+260>
0xb6f4f9a8 <memchr+40>: 00 00 52 e3 cmp r2, #0
0xb6f4f9ac <memchr+44>: 2d 00 00 0a beq 0xb6f4fa68 <memchr+232>
0xb6f4f9b0 <memchr+48>: 03 00 a0 e1 mov r0, r3
=> 0xb6f4f9b4 <memchr+52>: 01 c0 d3 e4 ldrb r12, [r3], #1
0xb6f4f9b8 <memchr+56>: 01 00 5c e1 cmp r12, r1
0xb6f4f9bc <memchr+60>: f6 ff ff 1a bne 0xb6f4f99c <memchr+28>
(gdb) bt
#0 0xb6f4f9b4 in memchr (src=src@entry=0x3b6a, c=c@entry=0x0, n=n@entry=0x7fffffff) at src/string/memchr.c:16
#1 0xb6f512b4 in strnlen (s=s@entry=0x3b6a <error: Cannot access memory at address 0x3b6a>, n=n@entry=0x7fffffff) at src/string/strnlen.c:5
#2 0xb6f19eb4 in printf_core (f=f@entry=0xb67d35b0, fmt=fmt@entry=0x101856 "%s.%06ld [%s] [%s:%d] ", ap=ap@entry=0xbe8f5a1c, nl_arg=nl_arg@entry=0xbe8f5a48, nl_type=, nl_type@entry=0xbe8f5a20) at
src/stdio/vfprintf.c:599
#3 0xb6f4b86c in vfprintf (f=0xb67d35b0, fmt=0x101856 "%s.%06ld [%s] [%s:%d] ", ap=...) at src/stdio/vfprintf.c:688
#4 0x0001d92c in aria2::OutputFile::printf (this=, format=0x101856 "%s.%06ld [%s] [%s:%d] ") at OutputFile.h:58
#5 0x00027910 in aria2::(anonymous namespace)::writeHeaderaria2::OutputFile (lineNum=0xba, sourceFile=0x10d842 "HttpServer.cc", level=aria2::Logger::A2_INFO, fp=...) at Logger.cc:136
#6 aria2::Logger::writeLog (this=0xb67cf78c, level=aria2::Logger::A2_INFO, sourceFile=0x10d842 "HttpServer.cc", lineNum=0xba, msg=0xb6766280 "HTTP Server received request\nPOST /jsonrpc HTTP/1.1\r\nHost: 192.168
.1.1:6800\r\nUser-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/118.0\r\nAccept: application/json, text/plain, *"..., msg@entry=0x10d842 "HttpServer.cc", trace=trace@entry=0x124806 "") a
t Logger.cc:196
#7 0x00028bf0 in aria2::Logger::log (this=, level=, sourceFile=, lineNum=, msg=0xb6766280 "HTTP Server received request\nPOST /jsonrpc HTTP/1.1\r\nHost
: 192.168.1.1:6800\r\nUser-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/118.0\r\nAccept: application/json, text/plain, *"...) at Logger.cc:213
#8 0x00081708 in aria2::HttpServer::receiveRequest (this=0xb6774430) at /home/egorenar/Repositories/openwrt-rel/staging_dir/toolchain-arm_cortex-a15+neon-vfpv4_gcc-12.3.0_musl_eabi/arm-openwrt-linux-muslgnueabi/
include/c++/12.3.0/bits/basic_string.h:233
#9 aria2::HttpServerCommand::execute (this=0xb6772620) at HttpServerCommand.cc:194
#10 0x00076de4 in aria2::(anonymous namespace)::executeCommand (commands=..., statusFilter=aria2::Command::STATUS_ALL) at DownloadEngine.cc:139
#11 0x0001913c in aria2::DownloadEngine::run (oneshot=0x0, this=0xb67967e0) at DownloadEngine.cc:180
#12 aria2::MultiUrlRequestInfo::execute (this=0xb67dee6c) at MultiUrlRequestInfo.cc:361
#13 aria2::main (argv=, argc=) at main.cc:78
#14 main (argc=, argv=) at main.cc:91

(gdb) p tv
$13 = {
tv_sec = 0x652134fd,
tv_usec = 0x3b6a
}
(gdb) call sizeof(tv)
$14 = 0x10
(gdb) call sizeof(tv.tv_usec)
$15 = 0x8
(gdb) call sizeof(long)
$16 = 0x4
(gdb) call sizeof(unsigned long)
$17 = 0x4
(gdb) call sizeof(time_t)
$18 = 0x8

[tatsuhiro-t]

Thank you for PR. Merged now.