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Improve behaviour with too long commands/filenames.

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This commit is contained in:
Jordan Bracco 2020-05-14 18:42:33 +02:00
parent 04f393e7d1
commit 911a9eab1f
3 changed files with 93 additions and 26 deletions
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3
lib/gen_magic/server.ex
View file

@ -283,7 +283,7 @@ defmodule GenMagic.Server do
20 => :enotdir,
12 => :enomem,
24 => :emfile,
36 => :enametoolong,
36 => :enametoolong
}
@errno Map.keys(@errnos)
@ -292,6 +292,7 @@ defmodule GenMagic.Server do
{:ok, {mime_type, encoding, content}} -> {:ok, Result.build(mime_type, encoding, content)}
{:error, {errno, _}} when errno in @errno -> {:error, @errnos[errno]}
{:error, {errno, string}} -> {:error, "#{errno}: #{string}"}
{:error, _} = error -> error
end
end

65
src/apprentice.c
View file

@ -60,6 +60,11 @@
#define ERROR_BAD_TERM 4
#define ERROR_EI 5
// We use a bigger than possible valid command length (around 4111 bytes) to
// allow more precise errors when using too long paths.
#define COMMAND_LEN 8000
#define COMMAND_BUFFER_SIZE COMMAND_LEN + 1
#define MAGIC_FLAGS_COMMON (MAGIC_CHECK | MAGIC_ERROR)
magic_t magic_setup(int flags);
@ -70,14 +75,14 @@ void setup_options(int argc, char **argv);
void setup_options_file(char *optarg);
void setup_options_default();
void setup_system();
int process_command(byte *buf);
void process_line(char *line);
int process_command(uint16_t len, byte *buf);
void process_file(char *path, ei_x_buff *result);
void process_bytes(char *bytes, int size, ei_x_buff *result);
size_t read_cmd(byte *buf);
size_t write_cmd(byte *buf, size_t len);
void error(ei_x_buff *result, const char *error);
void handle_magic_error(magic_t handle, int errn, ei_x_buff *result);
void fdseek(uint16_t count);
struct magic_file {
struct magic_file *prev;
@ -103,29 +108,35 @@ int main(int argc, char **argv) {
if (ei_x_free(&ok_buf) != 0)
exit(ERROR_EI);
byte buf[4112];
while (read_cmd(buf) > 0) {
process_command(buf);
byte buf[COMMAND_BUFFER_SIZE];
uint16_t len;
while ((len = read_cmd(buf)) > 0) {
process_command(len, buf);
}
return 255;
}
int process_command(byte *buf) {
int process_command(uint16_t len, byte *buf) {
ei_x_buff result;
char atom[128];
int index, version, arity, termtype, termsize;
index = 0;
if (ei_decode_version(buf, &index, &version) != 0) {
exit(ERROR_BAD_TERM);
}
// Initialize result
if (ei_x_new_with_version(&result) || ei_x_encode_tuple_header(&result, 2)) {
exit(ERROR_EI);
}
if (len >= COMMAND_LEN) {
error(&result, "badarg");
return 1;
}
if (ei_decode_version(buf, &index, &version) != 0) {
exit(ERROR_BAD_TERM);
}
if (ei_decode_tuple_header(buf, &index, &arity) != 0) {
error(&result, "badarg");
return 1;
@ -145,11 +156,16 @@ int process_command(byte *buf) {
char path[4097];
ei_get_type(buf, &index, &termtype, &termsize);
if (termtype == ERL_BINARY_EXT && termsize < 4096) {
long bin_length;
ei_decode_binary(buf, &index, path, &bin_length);
path[termsize] = '\0';
process_file(path, &result);
if (termtype == ERL_BINARY_EXT) {
if (termsize < 4096) {
long bin_length;
ei_decode_binary(buf, &index, path, &bin_length);
path[termsize] = '\0';
process_file(path, &result);
} else {
error(&result, "enametoolong");
return 1;
}
} else {
error(&result, "badarg");
return 1;
@ -176,6 +192,7 @@ int process_command(byte *buf) {
return 1;
}
// Empty the buffer.
write_cmd(result.buff, result.index);
if (ei_x_free(&result) != 0) {
@ -386,9 +403,15 @@ size_t read_cmd(byte *buf) {
}
uint16_t len16 = *(uint16_t *)buf;
len16 = ntohs(len16);
if (len16 > 4111) {
exit(ERROR_BAD_TERM);
// Buffer isn't large enough: just return possible len, without reading.
// Up to the caller of verifying the size again and return an error.
// buf left unchanged.
if (len16 > COMMAND_LEN) {
fdseek(len16);
return len16;
}
return read_exact(buf, len16);
}
@ -412,3 +435,11 @@ void error(ei_x_buff *result, const char *error) {
if (ei_x_free(result) != 0)
exit(ERROR_EI);
}
void fdseek(uint16_t count) {
int i = 0;
while (i < count) {
getchar();
i += 1;
}
}

51
test/gen_magic/apprentice_test.exs
View file

@ -1,6 +1,8 @@
defmodule GenMagic.ApprenticeTest do
use GenMagic.MagicCase
@tmp_path "/tmp/testgenmagicx"
test "sends ready" do
port = Port.open(GenMagic.Config.get_port_name(), GenMagic.Config.get_port_options([]))
assert_ready(port)
@ -85,19 +87,39 @@ defmodule GenMagic.ApprenticeTest do
end
test "works with big file path", %{port: port} do
file = too_big() <> "/a"
File.mkdir_p!(too_big())
File.touch!(file)
on_exit(fn -> File.rm_rf!("/tmp/testmagicex/") end)
send(port, {self(), {:command, :erlang.term_to_binary({:file, file})}})
# Test with longest valid path.
{dir, bigfile} = too_big(@tmp_path, "/a")
File.mkdir_p!(dir)
File.touch!(bigfile)
on_exit(fn -> File.rm_rf!(@tmp_path) end)
send(port, {self(), {:command, :erlang.term_to_binary({:file, bigfile})}})
assert_receive {^port, {:data, data}}
assert {:ok, _} = :erlang.binary_to_term(data)
refute_receive _
file = too_big() <> "/aaaaaaaaaa"
# This path should be long enough for buffers, but larger than a valid path name. Magic will return an errno 36.
file = @tmp_path <> String.duplicate("a", 256)
send(port, {self(), {:command, :erlang.term_to_binary({:file, file})}})
assert_receive {^port, {:data, data}}
assert {:error, {36, _}} = :erlang.binary_to_term(data)
refute_receive _
# Theses filename should be too big for the path buffer.
file = bigfile <> "aaaaaaaaaa"
send(port, {self(), {:command, :erlang.term_to_binary({:file, file})}})
assert_receive {^port, {:data, data}}
assert {:error, :enametoolong} = :erlang.binary_to_term(data)
refute_receive _
# This call should be larger than the COMMAND_BUFFER_SIZE. Ensure nothing bad happens!
file = String.duplicate(bigfile, 4)
send(port, {self(), {:command, :erlang.term_to_binary({:file, file})}})
assert_receive {^port, {:data, data}}
assert {:error, :badarg} = :erlang.binary_to_term(data)
refute_receive _
# We re-run a valid call to ensure the buffer/... haven't been corrupted in port land.
send(port, {self(), {:command, :erlang.term_to_binary({:file, bigfile})}})
assert_receive {^port, {:data, data}}
assert {:ok, _} = :erlang.binary_to_term(data)
refute_receive _
end
end
@ -106,7 +128,20 @@ defmodule GenMagic.ApprenticeTest do
assert :ready == :erlang.binary_to_term(data)
end
def too_big do
"/tmp/testmagicex/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
def too_big(path, filename, limit \\ 4095) do
last_len = byte_size(filename)
path_len = byte_size(path)
needed = limit - (last_len + path_len)
extra = make_too_big(needed, "")
{path <> extra, path <> extra <> filename}
end
def make_too_big(needed, acc) when needed <= 255 do
acc <> "/" <> String.duplicate("a", needed - 1)
end
def make_too_big(needed, acc) do
acc = acc <> "/" <> String.duplicate("a", 254)
make_too_big(needed - 255, acc)
end
end