What is the difference between a direct and indirect leak?

I got the following output from the LeakSanitizer tool. What is the difference between a direct and indirect leak, as the tool understands it?

13: ==29107==ERROR: LeakSanitizer: detected memory leaks
13: 
13: Direct leak of 288 byte(s) in 6 object(s) allocated from:
13:     #0 0x7f2ce0089050 in __interceptor_malloc (/nix/store/zahs1kwq4742f6l6h7yy4mdj44zzc1kd-gcc-7-20170409-lib/lib/libasan.so+0xd9050)
13:     #1 0x7f2cdfb974fe in qdr_core_subscribe ../src/router_core/route_tables.c:149
13:     #2 0x7f2cdfb47ff0 in IoAdapter_init ../src/python_embedded.c:548
13:     #3 0x7f2cde966ecd in type_call (/nix/store/1snk2wkpv97an87pk1842fgskl1vqhkr-python-2.7.14/lib/libpython2.7.so.1.0+0x9fecd)
13: 
13: Indirect leak of 2368 byte(s) in 1 object(s) allocated from:
13:     #0 0x7f2ce0089b88 in __interceptor_posix_memalign (/nix/store/zahs1kwq4742f6l6h7yy4mdj44zzc1kd-gcc-7-20170409-lib/lib/libasan.so+0xd9b88)
13:     #1 0x7f2cdfbcc8ea in qd_alloc ../src/alloc_pool.c:182
13:     #2 0x7f2cdfbb6c6b in qd_server_connection ../src/server.c:500
13:     #3 0x7f2cdfbbe27d in on_accept ../src/server.c:531
13:     #4 0x7f2cdfbbe27d in handle_listener ../src/server.c:701
13:     #5 0x7f2cdfbbe27d in handle ../src/server.c:844
13:     #6 0x7f2cdfbc2837 in thread_run ../src/server.c:921
13:     #7 0x7f2cdf0ba233 in start_thread (/nix/store/zpg78y1mf0di6127q6r51kgx2q8cxsvv-glibc-2.25-49/lib/libpthread.so.0+0x7233)
[...]

The accepted answer isn't quite correct. In particular

Stated another way, indirect leaks are a result of direct leaks.

is wrong in that it's possible to have only indirect leaks. This situation may arise when a self-referential structure is built and leaked.

Example:

#include <malloc.h>

struct Foo {
  struct Foo *other;
};

void fn(int depth)
{
  if (depth > 0) {
    // recursion is only necessary to avoid LSan finding "stray" pointers
    // and not reporting any leaks at all.
    fn(depth - 1);
  } else {
    struct Foo *f1 = malloc(sizeof(*f1));
    struct Foo *f2 = malloc(sizeof(*f2));
    f1->other = f2;
    f2->other = f1;
  }
}

int main()
{
  fn(10);
  return 0;
}

clang -g -fsanitize=address  t.c && ./a.out

=================================================================
==845196==ERROR: LeakSanitizer: detected memory leaks

Indirect leak of 8 byte(s) in 1 object(s) allocated from:
    #0 0x49832d in malloc (/tmp/a.out+0x49832d)
    #1 0x4c7f8e in fn /tmp/t.c:15:22
    #2 0x4c7f71 in fn /tmp/t.c:12:5
    #3 0x4c7f71 in fn /tmp/t.c:12:5
    #4 0x4c7f71 in fn /tmp/t.c:12:5
    #5 0x4c7f71 in fn /tmp/t.c:12:5
    #6 0x4c7f71 in fn /tmp/t.c:12:5
    #7 0x4c7f71 in fn /tmp/t.c:12:5
    #8 0x4c7f71 in fn /tmp/t.c:12:5
    #9 0x4c7f71 in fn /tmp/t.c:12:5
    #10 0x4c7f71 in fn /tmp/t.c:12:5
    #11 0x4c7f71 in fn /tmp/t.c:12:5
    #12 0x4c8028 in main /tmp/t.c:23:3
    #13 0x7f147d3a7d09 in __libc_start_main csu/../csu/libc-start.c:308:16

Indirect leak of 8 byte(s) in 1 object(s) allocated from:
    #0 0x49832d in malloc (/tmp/a.out+0x49832d)
    #1 0x4c7f80 in fn /tmp/t.c:14:22
    #2 0x4c7f71 in fn /tmp/t.c:12:5
    #3 0x4c7f71 in fn /tmp/t.c:12:5
    #4 0x4c7f71 in fn /tmp/t.c:12:5
    #5 0x4c7f71 in fn /tmp/t.c:12:5
    #6 0x4c7f71 in fn /tmp/t.c:12:5
    #7 0x4c7f71 in fn /tmp/t.c:12:5
    #8 0x4c7f71 in fn /tmp/t.c:12:5
    #9 0x4c7f71 in fn /tmp/t.c:12:5
    #10 0x4c7f71 in fn /tmp/t.c:12:5
    #11 0x4c7f71 in fn /tmp/t.c:12:5
    #12 0x4c8028 in main /tmp/t.c:23:3
    #13 0x7f147d3a7d09 in __libc_start_main csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: 16 byte(s) leaked in 2 allocation(s).

Note: no direct leaks, only indirect ones.