1 | use alloc::vec::Vec; |
2 | |
3 | use crate::read::{Bytes, ReadError, ReadRef, Result, StringTable}; |
4 | use crate::{elf, endian}; |
5 | |
6 | use super::FileHeader; |
7 | |
8 | /// A version index. |
9 | #[derive (Debug, Default, Clone, Copy)] |
10 | pub struct VersionIndex(pub u16); |
11 | |
12 | impl VersionIndex { |
13 | /// Return the version index. |
14 | pub fn index(&self) -> u16 { |
15 | self.0 & elf::VERSYM_VERSION |
16 | } |
17 | |
18 | /// Return true if it is the local index. |
19 | pub fn is_local(&self) -> bool { |
20 | self.index() == elf::VER_NDX_LOCAL |
21 | } |
22 | |
23 | /// Return true if it is the global index. |
24 | pub fn is_global(&self) -> bool { |
25 | self.index() == elf::VER_NDX_GLOBAL |
26 | } |
27 | |
28 | /// Return the hidden flag. |
29 | pub fn is_hidden(&self) -> bool { |
30 | self.0 & elf::VERSYM_HIDDEN != 0 |
31 | } |
32 | } |
33 | |
34 | /// A version definition or requirement. |
35 | /// |
36 | /// This is derived from entries in the [`elf::SHT_GNU_VERDEF`] and [`elf::SHT_GNU_VERNEED`] sections. |
37 | #[derive (Debug, Default, Clone, Copy)] |
38 | pub struct Version<'data> { |
39 | name: &'data [u8], |
40 | hash: u32, |
41 | // Used to keep track of valid indices in `VersionTable`. |
42 | valid: bool, |
43 | } |
44 | |
45 | impl<'data> Version<'data> { |
46 | /// Return the version name. |
47 | pub fn name(&self) -> &'data [u8] { |
48 | self.name |
49 | } |
50 | |
51 | /// Return hash of the version name. |
52 | pub fn hash(&self) -> u32 { |
53 | self.hash |
54 | } |
55 | } |
56 | |
57 | /// A table of version definitions and requirements. |
58 | /// |
59 | /// It allows looking up the version information for a given symbol index. |
60 | /// |
61 | /// This is derived from entries in the [`elf::SHT_GNU_VERSYM`], [`elf::SHT_GNU_VERDEF`] |
62 | /// and [`elf::SHT_GNU_VERNEED`] sections. |
63 | /// |
64 | /// Returned by [`SectionTable::versions`](super::SectionTable::versions). |
65 | #[derive (Debug, Clone)] |
66 | pub struct VersionTable<'data, Elf: FileHeader> { |
67 | symbols: &'data [elf::Versym<Elf::Endian>], |
68 | versions: Vec<Version<'data>>, |
69 | } |
70 | |
71 | impl<'data, Elf: FileHeader> Default for VersionTable<'data, Elf> { |
72 | fn default() -> Self { |
73 | VersionTable { |
74 | symbols: &[], |
75 | versions: Vec::new(), |
76 | } |
77 | } |
78 | } |
79 | |
80 | impl<'data, Elf: FileHeader> VersionTable<'data, Elf> { |
81 | /// Parse the version sections. |
82 | pub fn parse<R: ReadRef<'data>>( |
83 | endian: Elf::Endian, |
84 | versyms: &'data [elf::Versym<Elf::Endian>], |
85 | verdefs: Option<VerdefIterator<'data, Elf>>, |
86 | verneeds: Option<VerneedIterator<'data, Elf>>, |
87 | strings: StringTable<'data, R>, |
88 | ) -> Result<Self> { |
89 | let mut max_index = 0; |
90 | if let Some(mut verdefs) = verdefs.clone() { |
91 | while let Some((verdef, _)) = verdefs.next()? { |
92 | if verdef.vd_flags.get(endian) & elf::VER_FLG_BASE != 0 { |
93 | continue; |
94 | } |
95 | let index = verdef.vd_ndx.get(endian) & elf::VERSYM_VERSION; |
96 | if max_index < index { |
97 | max_index = index; |
98 | } |
99 | } |
100 | } |
101 | if let Some(mut verneeds) = verneeds.clone() { |
102 | while let Some((_, mut vernauxs)) = verneeds.next()? { |
103 | while let Some(vernaux) = vernauxs.next()? { |
104 | let index = vernaux.vna_other.get(endian) & elf::VERSYM_VERSION; |
105 | if max_index < index { |
106 | max_index = index; |
107 | } |
108 | } |
109 | } |
110 | } |
111 | |
112 | // Indices should be sequential, but this could be up to |
113 | // 32k * size_of::<Version>() if max_index is bad. |
114 | let mut versions = vec![Version::default(); max_index as usize + 1]; |
115 | |
116 | if let Some(mut verdefs) = verdefs { |
117 | while let Some((verdef, mut verdauxs)) = verdefs.next()? { |
118 | if verdef.vd_flags.get(endian) & elf::VER_FLG_BASE != 0 { |
119 | continue; |
120 | } |
121 | let index = verdef.vd_ndx.get(endian) & elf::VERSYM_VERSION; |
122 | if index <= elf::VER_NDX_GLOBAL { |
123 | // TODO: return error? |
124 | continue; |
125 | } |
126 | if let Some(verdaux) = verdauxs.next()? { |
127 | versions[usize::from(index)] = Version { |
128 | name: verdaux.name(endian, strings)?, |
129 | hash: verdef.vd_hash.get(endian), |
130 | valid: true, |
131 | }; |
132 | } |
133 | } |
134 | } |
135 | if let Some(mut verneeds) = verneeds { |
136 | while let Some((_, mut vernauxs)) = verneeds.next()? { |
137 | while let Some(vernaux) = vernauxs.next()? { |
138 | let index = vernaux.vna_other.get(endian) & elf::VERSYM_VERSION; |
139 | if index <= elf::VER_NDX_GLOBAL { |
140 | // TODO: return error? |
141 | continue; |
142 | } |
143 | versions[usize::from(index)] = Version { |
144 | name: vernaux.name(endian, strings)?, |
145 | hash: vernaux.vna_hash.get(endian), |
146 | valid: true, |
147 | }; |
148 | } |
149 | } |
150 | } |
151 | |
152 | Ok(VersionTable { |
153 | symbols: versyms, |
154 | versions, |
155 | }) |
156 | } |
157 | |
158 | /// Return true if the version table is empty. |
159 | pub fn is_empty(&self) -> bool { |
160 | self.symbols.is_empty() |
161 | } |
162 | |
163 | /// Return version index for a given symbol index. |
164 | pub fn version_index(&self, endian: Elf::Endian, index: usize) -> VersionIndex { |
165 | let version_index = match self.symbols.get(index) { |
166 | Some(x) => x.0.get(endian), |
167 | // Ideally this would be VER_NDX_LOCAL for undefined symbols, |
168 | // but currently there are no checks that need this distinction. |
169 | None => elf::VER_NDX_GLOBAL, |
170 | }; |
171 | VersionIndex(version_index) |
172 | } |
173 | |
174 | /// Return version information for a given symbol version index. |
175 | /// |
176 | /// Returns `Ok(None)` for local and global versions. |
177 | /// Returns `Err(_)` if index is invalid. |
178 | pub fn version(&self, index: VersionIndex) -> Result<Option<&Version<'data>>> { |
179 | if index.index() <= elf::VER_NDX_GLOBAL { |
180 | return Ok(None); |
181 | } |
182 | self.versions |
183 | .get(usize::from(index.index())) |
184 | .filter(|version| version.valid) |
185 | .read_error("Invalid ELF symbol version index" ) |
186 | .map(Some) |
187 | } |
188 | |
189 | /// Return true if the given symbol index satisfies the requirements of `need`. |
190 | /// |
191 | /// Returns false for any error. |
192 | /// |
193 | /// Note: this function hasn't been fully tested and is likely to be incomplete. |
194 | pub fn matches(&self, endian: Elf::Endian, index: usize, need: Option<&Version<'_>>) -> bool { |
195 | let version_index = self.version_index(endian, index); |
196 | let def = match self.version(version_index) { |
197 | Ok(def) => def, |
198 | Err(_) => return false, |
199 | }; |
200 | match (def, need) { |
201 | (Some(def), Some(need)) => need.hash == def.hash && need.name == def.name, |
202 | (None, Some(_need)) => { |
203 | // Version must be present if needed. |
204 | false |
205 | } |
206 | (Some(_def), None) => { |
207 | // For a dlsym call, use the newest version. |
208 | // TODO: if not a dlsym call, then use the oldest version. |
209 | !version_index.is_hidden() |
210 | } |
211 | (None, None) => true, |
212 | } |
213 | } |
214 | } |
215 | |
216 | /// An iterator for the entries in an ELF [`elf::SHT_GNU_VERDEF`] section. |
217 | #[derive (Debug, Clone)] |
218 | pub struct VerdefIterator<'data, Elf: FileHeader> { |
219 | endian: Elf::Endian, |
220 | data: Bytes<'data>, |
221 | } |
222 | |
223 | impl<'data, Elf: FileHeader> VerdefIterator<'data, Elf> { |
224 | pub(super) fn new(endian: Elf::Endian, data: &'data [u8]) -> Self { |
225 | VerdefIterator { |
226 | endian, |
227 | data: Bytes(data), |
228 | } |
229 | } |
230 | |
231 | /// Return the next `Verdef` entry. |
232 | pub fn next( |
233 | &mut self, |
234 | ) -> Result<Option<(&'data elf::Verdef<Elf::Endian>, VerdauxIterator<'data, Elf>)>> { |
235 | if self.data.is_empty() { |
236 | return Ok(None); |
237 | } |
238 | |
239 | let verdef = self |
240 | .data |
241 | .read_at::<elf::Verdef<_>>(0) |
242 | .read_error("ELF verdef is too short" )?; |
243 | |
244 | let mut verdaux_data = self.data; |
245 | verdaux_data |
246 | .skip(verdef.vd_aux.get(self.endian) as usize) |
247 | .read_error("Invalid ELF vd_aux" )?; |
248 | let verdaux = |
249 | VerdauxIterator::new(self.endian, verdaux_data.0, verdef.vd_cnt.get(self.endian)); |
250 | |
251 | let next = verdef.vd_next.get(self.endian); |
252 | if next != 0 { |
253 | self.data |
254 | .skip(next as usize) |
255 | .read_error("Invalid ELF vd_next" )?; |
256 | } else { |
257 | self.data = Bytes(&[]); |
258 | } |
259 | Ok(Some((verdef, verdaux))) |
260 | } |
261 | } |
262 | |
263 | /// An iterator for the auxiliary records for an entry in an ELF [`elf::SHT_GNU_VERDEF`] section. |
264 | #[derive (Debug, Clone)] |
265 | pub struct VerdauxIterator<'data, Elf: FileHeader> { |
266 | endian: Elf::Endian, |
267 | data: Bytes<'data>, |
268 | count: u16, |
269 | } |
270 | |
271 | impl<'data, Elf: FileHeader> VerdauxIterator<'data, Elf> { |
272 | pub(super) fn new(endian: Elf::Endian, data: &'data [u8], count: u16) -> Self { |
273 | VerdauxIterator { |
274 | endian, |
275 | data: Bytes(data), |
276 | count, |
277 | } |
278 | } |
279 | |
280 | /// Return the next `Verdaux` entry. |
281 | pub fn next(&mut self) -> Result<Option<&'data elf::Verdaux<Elf::Endian>>> { |
282 | if self.count == 0 { |
283 | return Ok(None); |
284 | } |
285 | |
286 | let verdaux = self |
287 | .data |
288 | .read_at::<elf::Verdaux<_>>(0) |
289 | .read_error("ELF verdaux is too short" )?; |
290 | |
291 | self.data |
292 | .skip(verdaux.vda_next.get(self.endian) as usize) |
293 | .read_error("Invalid ELF vda_next" )?; |
294 | self.count -= 1; |
295 | Ok(Some(verdaux)) |
296 | } |
297 | } |
298 | |
299 | /// An iterator for the entries in an ELF [`elf::SHT_GNU_VERNEED`] section. |
300 | #[derive (Debug, Clone)] |
301 | pub struct VerneedIterator<'data, Elf: FileHeader> { |
302 | endian: Elf::Endian, |
303 | data: Bytes<'data>, |
304 | } |
305 | |
306 | impl<'data, Elf: FileHeader> VerneedIterator<'data, Elf> { |
307 | pub(super) fn new(endian: Elf::Endian, data: &'data [u8]) -> Self { |
308 | VerneedIterator { |
309 | endian, |
310 | data: Bytes(data), |
311 | } |
312 | } |
313 | |
314 | /// Return the next `Verneed` entry. |
315 | pub fn next( |
316 | &mut self, |
317 | ) -> Result< |
318 | Option<( |
319 | &'data elf::Verneed<Elf::Endian>, |
320 | VernauxIterator<'data, Elf>, |
321 | )>, |
322 | > { |
323 | if self.data.is_empty() { |
324 | return Ok(None); |
325 | } |
326 | |
327 | let verneed = self |
328 | .data |
329 | .read_at::<elf::Verneed<_>>(0) |
330 | .read_error("ELF verneed is too short" )?; |
331 | |
332 | let mut vernaux_data = self.data; |
333 | vernaux_data |
334 | .skip(verneed.vn_aux.get(self.endian) as usize) |
335 | .read_error("Invalid ELF vn_aux" )?; |
336 | let vernaux = |
337 | VernauxIterator::new(self.endian, vernaux_data.0, verneed.vn_cnt.get(self.endian)); |
338 | |
339 | let next = verneed.vn_next.get(self.endian); |
340 | if next != 0 { |
341 | self.data |
342 | .skip(next as usize) |
343 | .read_error("Invalid ELF vn_next" )?; |
344 | } else { |
345 | self.data = Bytes(&[]); |
346 | } |
347 | Ok(Some((verneed, vernaux))) |
348 | } |
349 | } |
350 | |
351 | /// An iterator for the auxiliary records for an entry in an ELF [`elf::SHT_GNU_VERNEED`] section. |
352 | #[derive (Debug, Clone)] |
353 | pub struct VernauxIterator<'data, Elf: FileHeader> { |
354 | endian: Elf::Endian, |
355 | data: Bytes<'data>, |
356 | count: u16, |
357 | } |
358 | |
359 | impl<'data, Elf: FileHeader> VernauxIterator<'data, Elf> { |
360 | pub(super) fn new(endian: Elf::Endian, data: &'data [u8], count: u16) -> Self { |
361 | VernauxIterator { |
362 | endian, |
363 | data: Bytes(data), |
364 | count, |
365 | } |
366 | } |
367 | |
368 | /// Return the next `Vernaux` entry. |
369 | pub fn next(&mut self) -> Result<Option<&'data elf::Vernaux<Elf::Endian>>> { |
370 | if self.count == 0 { |
371 | return Ok(None); |
372 | } |
373 | |
374 | let vernaux = self |
375 | .data |
376 | .read_at::<elf::Vernaux<_>>(0) |
377 | .read_error("ELF vernaux is too short" )?; |
378 | |
379 | self.data |
380 | .skip(vernaux.vna_next.get(self.endian) as usize) |
381 | .read_error("Invalid ELF vna_next" )?; |
382 | self.count -= 1; |
383 | Ok(Some(vernaux)) |
384 | } |
385 | } |
386 | |
387 | impl<Endian: endian::Endian> elf::Verdaux<Endian> { |
388 | /// Parse the version name from the string table. |
389 | pub fn name<'data, R: ReadRef<'data>>( |
390 | &self, |
391 | endian: Endian, |
392 | strings: StringTable<'data, R>, |
393 | ) -> Result<&'data [u8]> { |
394 | stringsResult<&[u8], ()> |
395 | .get(self.vda_name.get(endian)) |
396 | .read_error("Invalid ELF vda_name" ) |
397 | } |
398 | } |
399 | |
400 | impl<Endian: endian::Endian> elf::Verneed<Endian> { |
401 | /// Parse the file from the string table. |
402 | pub fn file<'data, R: ReadRef<'data>>( |
403 | &self, |
404 | endian: Endian, |
405 | strings: StringTable<'data, R>, |
406 | ) -> Result<&'data [u8]> { |
407 | stringsResult<&[u8], ()> |
408 | .get(self.vn_file.get(endian)) |
409 | .read_error("Invalid ELF vn_file" ) |
410 | } |
411 | } |
412 | |
413 | impl<Endian: endian::Endian> elf::Vernaux<Endian> { |
414 | /// Parse the version name from the string table. |
415 | pub fn name<'data, R: ReadRef<'data>>( |
416 | &self, |
417 | endian: Endian, |
418 | strings: StringTable<'data, R>, |
419 | ) -> Result<&'data [u8]> { |
420 | stringsResult<&[u8], ()> |
421 | .get(self.vna_name.get(endian)) |
422 | .read_error("Invalid ELF vna_name" ) |
423 | } |
424 | } |
425 | |