ehmry/genode
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libc: fill stdio descriptors even if invalid

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Stdin, stdout, and stderr are mapped to descriptors 0, 1, and 2
respectively. If these first three descriptors are not allocated before
the application becomes active then normal files and sockets can be
opened under these numbers, potentially causing unexpected application
behavior.

Fix #2628
This commit is contained in:
Ehmry - 2017-12-31 22:31:28 -06:00 committed by Christian Helmuth
parent 61e1bed2c2
commit 36104098ad
3 changed files with 6 additions and 3 deletions
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2
repos/libports/run/ldso.run
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@ -77,7 +77,7 @@ compare_output_to {
[init -> test-ldso] lib_1_local_3 12345676
[init -> test-ldso] lib_1_pod_1 8070604d
[init -> test-ldso] Libc::read:
[init -> test-ldso] Error: no plugin found for read(0)
[init -> test-ldso] Error: no plugin found for read(3)
[init -> test-ldso] Libc::abs(-10): 10
[init -> test-ldso]
[init -> test-ldso] Catch exceptions in program

5
repos/libports/src/lib/libc/vfs_plugin.h
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@ -70,7 +70,10 @@ class Libc::Vfs_plugin : public Libc::Plugin
if (fd->fd_path) { Genode::warning("may leak former FD path memory"); }
fd->fd_path = strdup(path.string());
} catch (Xml_node::Nonexistent_attribute) { }
} catch (Xml_node::Nonexistent_attribute) {
/* fill the stdio number with a EBADF */
Libc::file_descriptor_allocator()->alloc(nullptr, nullptr, libc_fd);
}
}
void _vfs_sync(Vfs::Vfs_handle *vfs_handle)

2
repos/libports/src/test/ldso/main.cc
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@ -211,7 +211,7 @@ void Libc::Component::construct(Libc::Env &env)
lib_1_local_3()->lib_1_local_3();
printf("lib_1_pod_1 %x\n", --pod_1);
int fd = 0;
int fd = STDERR_FILENO + 1;
char buf[2];
printf("Libc::read:\n");
Libc::read(fd, buf, 2);